Why resellers need better bookkeeping
Reselling is more complex than it looks. Profitability depends on tight cost tracking:
- Item-level tracking. You need the profit on each item, not just monthly totals.
- Variable platform fees: eBay (12.9%), Poshmark (20%), Mercari (10%), Facebook Marketplace (free).
- Shipping costs vary by carrier, package size and buyer location.
- Sourcing channels: thrift stores, garage sales, wholesale, clearance, online arbitrage.
- Inventory management. Track what’s sold and what’s sitting, and calculate inventory value.
- Multi-platform selling. Cross-posting means sales come from different platforms.
SheetLink helps by syncing your bank transactions (platform deposits, sourcing purchases, shipping costs and supplies) to Google Sheets when you press Sync now. There you can track profit per item and overall business metrics.
How SheetLink helps resellers
Resale bookkeeping in a spreadsheet, at a fraction of the cost of inventory management software:
- Sync platform deposits from eBay, Poshmark, Mercari, Depop and Vinted.
- Track sourcing costs: thrift store, yard sale and wholesale purchases.
- Monitor platform fees. See how much each marketplace takes from your sales.
- Track shipping expenses: USPS, UPS and FedEx charges, plus supplies (boxes, tape, labels).
- Calculate profit per item. Know which categories and sourcing channels are most profitable.
- Affordable pricing. Pro is $4.99 a month; List Perfectly is $30 a month and Vendoo $40 a month.
What to track for your resale business
SheetLink syncs every transaction, so you can organize your reseller finances:
Income sources
Expense categories
Calculate profit per item
Successful resellers track every item’s profitability. Here’s how to calculate it accurately.
Example: thrift store clothing flip
| Line | Amount |
|---|---|
| Sale price (Poshmark) | $48.00 |
| Poshmark fee (20%) | -$9.60 |
| Item cost (thrift store) | -$6.00 |
| Shipping label (Poshmark prepaid) | $0.00 |
| Packaging (poly mailer, tissue) | -$0.50 |
| Net profit | $31.90 (66% margin) |
| ROI | 532% ($31.90 profit / $6 cost) |
Example: eBay electronics flip
| Line | Amount |
|---|---|
| Sale price (eBay) | $125.00 |
| eBay final value fee (12.9% + $0.30) | -$16.43 |
| Item cost (yard sale) | -$25.00 |
| Shipping cost (USPS Priority) | -$12.50 |
| Packaging (box, bubble wrap) | -$2.00 |
| Promoted listing (5% ad fee) | -$6.25 |
| Net profit | $62.82 (50% margin) |
| ROI | 251% ($62.82 profit / $25 cost) |
Build formulas in Google Sheets to calculate this for each sale, and track which categories (clothing, electronics, vintage) have the best margins.
Platform fees breakdown
Understanding platform fees is critical for pricing and profitability.
eBay: 12.9% + $0.30 final value fee
eBay charges 12.9% + $0.30 on most categories. Some categories differ: guitars (3.5%), trading cards (12.35%). You get 250 free listings a month, then $0.35 a listing. Promoted listings are an optional 2-20% ad fee.
Poshmark: 20% on $15+, $2.95 under $15
Poshmark takes a 20% commission on sales of $15 and above, and a flat $2.95 on sales under $15. Shipping labels come at a flat rate ($7.97 for up to 5 lbs). No listing fees. Best for clothing and accessories.
Mercari: 10% + payment processing
Mercari charges a 10% selling fee plus payment processing (2.9% + $0.30). Lower fees than competitors, and prepaid shipping labels are available. Good for general merchandise, collectibles and electronics.
Facebook Marketplace: free (0% fees)
Facebook Marketplace has no selling fees for local pickup. The shipping option charges 5% or a $0.40 minimum. Best for large items, furniture and local sales. Use Venmo or Zelle for payment.
Track inventory and sourcing ROI
Smart resellers track which sourcing channels give the best ROI:
- Thrift stores (Goodwill, Value Village): high margin potential (400-1000% ROI) but time-intensive
- Yard and garage sales: the best prices, but inconsistent inventory, and seasonal
- Estate sales: quality items and vintage finds, but competitive with other resellers
- Retail arbitrage: clearance racks at Target, Walmart and TJ Maxx (lower margins, 30-50%)
- Online arbitrage: Amazon clearance, eBay lots (easier to scale, requires research)
- Wholesale: buy in bulk from distributors (lower per-unit margins, but volume)
Tag each inventory purchase in your sheet by sourcing channel. Calculate the average ROI per channel and focus your time on the highest-return sources.
Key metrics for resellers
Build these metrics in your SheetLink spreadsheet to monitor your business’s health:
| Metric | How to calculate it | Target |
|---|---|---|
| Profit margin % | (Net profit ÷ Sale price) × 100 | 40-60% |
| Average ROI | (Total profit ÷ Total COGS) × 100 | 200-500% |
| Inventory value | Total $ tied up in unsold items | Keep it low to improve cash flow |
| Sell-through rate | (Items sold ÷ Items listed) × 100 | 70%+ |
| Average days to sell | How long items sit before selling | Lower is better |
| Inventory turnover | Items sold ÷ Average inventory | 6-12x a year |
| ROI by category | Which item types (clothing, electronics, vintage) are most profitable | |
| ROI by sourcing channel | Which sourcing method gives the best returns |
How to set up your reseller tracker
Get your resale bookkeeping organized in under 15 minutes:
Install the SheetLink Chrome extension
Connect your business bank account
Connect your business credit card
Create your reseller finance sheet
Press Sync now
Add custom columns
Tag transactions
Build profit formulas
Manage dead stock and slow movers
Not every item sells quickly. Track aging inventory to keep less cash tied up:
30-60 days listed
Normal for most items. Watch the interest (views, likes, watchers), and consider a small price drop or promotion if there’s no traction.
60-90 days listed
Slow-moving inventory. Cut the price 10-20%, improve the photos and description, relist with better keywords, or bundle with other items.
90+ days listed (dead stock)
Consider a deep discount (30-50% off), donating for a tax write-off, or selling to wholesale buyers. Accept break-even or a small loss to free up cash for better inventory.
SheetLink vs. reseller software
| Tool | Cost | Best for |
|---|---|---|
| SheetLink | Free, or Pro at $4.99/month | Solo resellers, simple bookkeeping |
| List Perfectly | $30-70/month | Crossposting plus profit tracking |
| Vendoo | $40-80/month | Multi-platform automation |
| QuickBooks | $38-140/month | Full-time resellers with employees |
| Manual spreadsheet | Free (time cost) | Beginners, very small scale |
The SheetLink advantage: bank sync with full spreadsheet control, at a fraction of the cost. It suits resellers who want profit tracking without paying for crossposting features. Pair it with free listing tools for a complete workflow.
Tax season for resellers
Resellers file Schedule C (self-employment income) and track COGS carefully:
- Gross receipts: total sales from every platform. Synced deposits arrive net of platform fees, so add the fees back to get the gross figure
- COGS deduction: inventory purchases are deductible when items sell, not when you buy them
- Year-end inventory: calculate the value of unsold items, which affects COGS
- Business expenses: shipping, platform fees, supplies, mileage, storage
- Quarterly estimated taxes: pay 25-30% of net profit each quarter to avoid penalties
- 1099-K reporting: platforms send a 1099-K once your sales pass the IRS threshold; check it against your records
- Mileage deduction: track sourcing trips at the IRS standard mileage rate, which changes each year
Two example resellers
Jessica, a clothing reseller
Challenge: Jessica thrifted 50+ items a week but couldn’t tell which brands were most profitable, and wasted time on low-margin items.
Solution: SheetLink syncs her Poshmark and eBay payouts as they land in her bank account. She tags each sale by brand and category and calculates profit per item.
Result: Designer jeans returned 800% ROI while fast fashion averaged 200%. She focused her sourcing on high-end brands and more than doubled her monthly profit, from $2,000 to $4,200.
Tom, an electronics flipper
Challenge: Tom sourced from yard sales and online marketplaces but had $3,000 in dead stock that wasn’t selling on eBay.
Solution: SheetLink syncs his card purchases and eBay payouts. He calculated days-to-sell for each category and found the slow movers.
Result: He liquidated the dead stock at break-even and reinvested in faster-selling categories (gaming consoles, Apple products), cutting inventory from $8,000 to $4,500 on the same revenue, which freed $3,500 of cash.
Pricing
| Plan | Price | What you get |
|---|---|---|
| Free | $0 | 1 bank, your last 7 days, Google Sheets |
| Pro | $4.99/mo or $39.99/yr | Every bank you connect, up to 2 years of history, Google Sheets and Excel, priority email support |
| Max | $10.99/mo or $99/yr | Everything in Pro, plus investments, CLI automation, Postgres and SQLite output, and Claude |
Questions
How do resellers track profit per item?
Use SheetLink to sync the bank account where your platforms deposit sales, whenever you press Sync now, for weekly or monthly reviews. Tag each deposit by item SKU or listing, and track sourcing cost, platform fees, shipping costs and supplies. Then calculate: Sale Price - Sourcing Cost - Platform Fees - Shipping - Supplies = Net Profit per Item.
What fees do eBay and Poshmark resellers pay?
eBay charges final value fees (12.9% + $0.30 for most items), insertion fees for listings over the free limit, promoted listings fees (2-20%), and payment processing fees. Poshmark takes 20% on sales over $15 and $2.95 on sales under $15. Mercari charges 10% plus payment processing (2.9% + $0.30). SheetLink syncs your net deposits after fees, so you can track the total fee impact.
How do resellers calculate inventory value and sell-through rate?
Track what you’ve spent on unsold inventory by syncing your sourcing purchases with SheetLink. Inventory Value = Total Sourcing Costs for Unsold Items. Sell-Through Rate = (Items Sold ÷ Total Items Listed) × 100; aim for 70%+. Inventory turnover = Items Sold ÷ Average Inventory, which helps you manage cash flow and avoid dead stock.
Do resellers need to track quarterly taxes?
Yes. Resellers file Schedule C (self-employment income) and pay quarterly estimated taxes. Track gross sales, COGS (inventory purchases), platform fees, shipping and supplies in your SheetLink sheet. Calculate net profit each quarter and pay 25-30% of it in estimated taxes. Platforms send a 1099-K once your sales pass the IRS reporting threshold, so check it against your SheetLink records.