Retail Arbitrage Taxes: Resale Certificates, Sales Tax, and What You Owe
Two separate tax systems apply to this business and they get conflated constantly. Sales tax is what a state charges on a retail transaction. Income tax is what you owe on profit. They have different rules, different agencies, and different paperwork.
This is general information, not tax advice. Rules differ meaningfully by state, and if you’re operating at any scale a few hundred dollars with an accountant will pay for itself.
Sales tax when you buy
By default you pay sales tax on inventory purchases like any other shopper — 6 to 10 percent depending on the state, straight off your margin. On a $2,000 monthly sourcing budget, that’s $120 to $200 a month.
A resale certificate exempts purchases you’re buying to resell, because the theory of sales tax is that it’s collected once, from the final consumer. You’re not the final consumer.
Getting one:
- Register with your state’s tax authority — usually the Department of Revenue or equivalent. This gets you a sales tax permit or seller’s permit. Most states charge little or nothing.
- Receive your permit number.
- Complete a resale certificate form for each retailer. The certificate is a document you give the seller, not something you file with the state.
- Get it into the retailer’s system. Home Depot, Lowe’s, Walmart, Costco, and most other big-box chains have tax-exempt programs that issue you an ID to present at checkout.
The last step is the one people skip. A certificate sitting in a drawer saves nothing.
Important limits. The exemption is only for goods you intend to resell. Using it for personal purchases is tax fraud, and states do audit. Keep resale purchases on a separate card and separate receipts — the accounting hygiene is also what makes an audit boring rather than expensive.
Also note: some states require you to be registered in that state to use a certificate there, and a handful don’t accept out-of-state certificates at all. If you source across a state line, check both.
Sales tax when you sell
This got dramatically simpler after South Dakota v. Wayfair (2018) and the marketplace facilitator laws that followed.
Today, if you sell on Amazon, eBay, Walmart Marketplace, Mercari, or Etsy, the marketplace collects and remits sales tax for you in essentially all states that have it. You generally do not need to file sales tax returns for those sales.
Where you still have obligations:
- Direct sales — your own website, local cash sales, anything outside a facilitator platform.
- Filing zero returns. Many states require a registered seller to file returns even when the facilitator remitted everything and you owe nothing. Missing these produces penalties for a return that says zero.
- The state you’re registered in, which generally wants a return on a schedule regardless of activity.
That second point catches people. Registering for a resale certificate creates a filing obligation. It’s still worth it — the savings dwarf the nuisance — but put the deadlines in a calendar.
Track the buy price, keep the records
Endless records what an item cost before it dropped across thirteen retailers, which is the same figure your cost-of-goods records need.
Start freeIncome tax
Reselling profit is taxable income. If you’re a sole proprietor, it goes on Schedule C.
What’s deductible — the list is longer than most new sellers realize:
- Cost of goods sold
- Marketplace and payment processing fees
- Shipping, postage, and packing materials
- Mileage at the IRS standard rate, or actual vehicle expenses
- Software and subscriptions
- A home office, if the space is used regularly and exclusively for the business
- Business-use portion of a phone and internet
- Bank and merchant account fees
Mileage is usually the biggest one for retail arbitrage specifically, and it requires a contemporaneous log — date, destination, purpose, miles. An app that does this automatically is worth the few dollars.
Self-employment tax. Net profit above $400 owes self-employment tax on top of income tax, currently 15.3 percent covering both halves of Social Security and Medicare. This is the number that surprises people in April. If you’re profitable, make quarterly estimated payments rather than discovering the bill at once.
Form 1099-K. Payment processors and marketplaces report your gross payments. The threshold has moved repeatedly in recent years, so check the current one. Two things to understand about it: the amount reported is gross, before fees and refunds, so it will be higher than your actual income; and you owe tax on your profit whether or not a form gets issued.
Inventory accounting
Inventory is not deductible when you buy it. It becomes cost of goods sold when it sells. Buying $5,000 of inventory in December doesn’t create a $5,000 December deduction — it creates an asset that converts to an expense as it moves.
Small businesses under the gross receipts threshold can often use simplified methods that let them treat inventory as non-incidental materials and deduct it when sold or used. This is exactly the kind of question to ask an accountant once rather than guess at annually.
The records to keep
- Every purchase receipt, with the item and cost identifiable
- Marketplace settlement reports, monthly
- Mileage log
- Fee statements
- Inventory count at year end — what you’re holding and what it cost
Photograph paper receipts on the day you get them. Thermal receipts fade to blank within a year or two, and a faded receipt is not a record.
Frequently Asked Questions
Do I need a resale certificate for retail arbitrage?
You don’t need one to operate, but it exempts you from paying sales tax on inventory purchases, which is 6 to 10 percent of your cost of goods. Register with your state’s tax authority, then file a certificate with each retailer and enroll in their tax-exempt program so it applies at checkout.
Do I have to collect sales tax on items I sell?
Generally not on marketplace sales. Under marketplace facilitator laws, Amazon, eBay, Walmart, Mercari, and Etsy collect and remit sales tax on your behalf in essentially every state that levies it. Direct sales outside those platforms are your responsibility.
Is retail arbitrage income taxable?
Yes. Profit is reportable income, typically on Schedule C for a sole proprietor, and net profit above $400 also owes self-employment tax of 15.3 percent on top of income tax.
Can I deduct mileage for sourcing trips?
Yes, at the IRS standard mileage rate, provided you keep a contemporaneous log with dates, destinations, purpose, and miles. For retail arbitrage this is often the single largest deduction.
When do I deduct inventory I bought but haven’t sold?
Not when you buy it. Inventory becomes cost of goods sold when the item sells. Smaller businesses may qualify for simplified methods that change the timing — worth confirming with an accountant for your specific situation.
What is a 1099-K and will I get one?
It’s a form reporting the gross payments a marketplace or processor sent you. Thresholds have changed several times recently, so check the current one. The reported figure is gross, before fees and refunds, so it will exceed your actual profit — and you owe tax on the profit whether or not a form arrives.