What is the best app for reselling?

It depends on the job. A marketplace app (eBay, Poshmark, Mercari) is where the sale happens. A crosslister copies listings between marketplaces. Underpriced AI does the part before and after: it identifies the item from a photo, prices it from real eBay sold listings, writes and publishes the eBay listing, fills other marketplaces' forms from your desktop, and tracks cost and profit until the tax report.

Is there a free reseller app?

Your first scan is free with no card, and it is the full result: the item, the price and the sold listings behind it. The fee calculators and the eBay sold listings search are free with no signup. After that it is $0.25 a scan on pay as you go, or a plan from $5 a month.

Does it work on iPhone and Android?

Yes. There is an iOS app, an Android app and a full web app on the same account. Scan in the aisle on your phone, then list and manage the pile on a laptop.

Can it crosslist to Poshmark, Mercari and Facebook?

It helps you list there, and it is honest about how. On a desktop, the free extension fills the listing form on Facebook Marketplace, Poshmark, Mercari, Depop, Vinted, Whatnot, OfferUp and Etsy with your title, price, description and photos, and you pick the category and click Post. On a phone, a copy kit walks you through each field. It does not post to those marketplaces on its own and it does not delist them for you.

How accurate are the prices?

Every price comes with a range and the sold listings behind it, each one a link to eBay, so you can check the number before you trust it. We grade the prices every week against what items actually sold for and publish the result on the accuracy page, wins and misses.

Underpriced AI

The reseller app for the whole flip

Photograph it, see what it actually sold for, list it, and track the profit. One app from the shelf to the tax return.

Scan your first item free, no card See pricing

Then $0.25 a scan, or plans from $5 a month. 4,600+ resellers have priced $2.4M+ of items.

Updated September 28, 2026

A photo of a vintage lady head vase, ready to scan — One real thrift find. Paid $6, sold for $45.

One real thrift find. Paid $6, sold for $45.

The sales behind a price like this

In the 90 days to September 28, our archive captured 332 eBay sales matching “lady head vase”. The middle half went for $29.99 to $74.99.

The scan priced ours at $34.30, low in that spread; it sold for $45. Every scan lists the sold listings behind its price, each one a link to eBay, like these three from the archive:

The vase is a real find by a reseller in our family. Sales from our archive of eBay sold listings, read September 28, 2026.

Graded every week against 379 real sales, published win or lose. See the grade

The figures

On the 195 sales in the last 90 days where the seller set their own price, the typical gap between our estimate and the sale was 38%, and 41.5% sold inside our range. That is why every result shows a range and the sales, not one confident number.

Who it is for

Built for the way you source

Five kinds of reseller, one app. Each card says what does the work for you.

Thrift flippers

Scan it on the shelf and see the net after fees before you pay. A sourcing calculator takes the tag price and tells you if it is worth it.

Estate sale pickers

Sale Finder (Pro Plus and up) opens EstateSales.NET, GSALR, YardSaleSearch and AuctionZip for your ZIP. Batch scan up to ten items at a time and the haul is priced before you load the car.

Bin store divers

Books, CDs and records price from the barcode in the photo. Everything else prices from one picture, so the whole cart gets a number in minutes.

Card and collectible sellers

A card, a coin or a figure scans like anything else: one photo, identified, priced from eBay sold listings. The eBay listing sets graded or ungraded condition where the category asks for it. There is no bulk card scanner.

Full time eBay stores

Import your active eBay listings, sync the sales of what you list through the app, print SKU labels, and see your unlisted pile ranked by what it is costing you.

Price

What it really sold for

Identify from a photo: Brand, model, maker, edition and condition. Up to 12 photos of one item count as one scan.
Sold listings you can open: Five sources of real sold prices, tried in order, each sale a link to eBay. Asking prices are shown apart.
Three prices and the net: Sells fast, market and patient prices, and what lands in your pocket after fees.
Barcodes, when they help: An ISBN reads Google Books; a CD or record barcode reads Discogs, from the same photo.

How the scan works

List

Listed without retyping

One tap to eBay: Title, description and item specifics filled in. Ten eBay countries and Bonanza, and Discogs for records.
Other marketplaces: The free desktop extension fills the form on Facebook Marketplace, Poshmark, Mercari, Depop, Vinted, Whatnot, OfferUp and Etsy; you click Post. A phone gets a copy kit.
Photos ready to post: Background removal, rotate, reorder and pick the main photo, free on every plan.
Every connection: Which marketplaces publish directly, which the extension fills, and which get a copy kit.

The eBay listing tool

The List on eBay sheet with the title, description and price filled in

Track

The pile, the profit, the taxes

Inventory with SKUs: Cost, where found, storage location and your SKU, which goes to eBay as the custom label. Print barcode labels and scan them to find the item.
Sales sync from eBay: When an item you listed through the app sells on eBay, the sale price, fees and shipping come in on their own.
Profit and analytics: Profit per item, sourcing ROI, aging stock and category reports on Pro Plus and up.
Tax time: A Schedule C ready CSV and donation valuation reports on Pro Plus and up.

Inventory and profit

Unlisted items ranked by what they are costing you, with the price and the expected profit on each

Straight answers

What it does not do

So nobody signs up expecting something else.

It does not auto-crosspost. The extension fills the form on your computer and you click Post.
It does not delist other marketplaces. When something sells elsewhere it can end the eBay listing for you, and it reminds you about the rest.
The form-filling extension runs on a desktop browser, not on a phone.
Publishing to eBay needs a plan or unused scan pack credits. Pay as you go alone covers scans, not publishing.

Every marketplace and how it connects is on the integrations page. Comparing tools? See Underpriced AI against the alternatives.

Questions

What is the best app for reselling?: It depends on the job. A marketplace app (eBay, Poshmark, Mercari) is where the sale happens. A crosslister copies listings between marketplaces. Underpriced AI does the part before and after: it identifies the item from a photo, prices it from real eBay sold listings, writes and publishes the eBay listing, fills other marketplaces' forms from your desktop, and tracks cost and profit until the tax report.
Is there a free reseller app?: Your first scan is free with no card, and it is the full result: the item, the price and the sold listings behind it. The fee calculators and the eBay sold listings search are free with no signup. After that it is $0.25 a scan on pay as you go, or a plan from $5 a month.
Does it work on iPhone and Android?: Yes. There is an iOS app, an Android app and a full web app on the same account. Scan in the aisle on your phone, then list and manage the pile on a laptop.
Can it crosslist to Poshmark, Mercari and Facebook?: It helps you list there, and it is honest about how. On a desktop, the free extension fills the listing form on Facebook Marketplace, Poshmark, Mercari, Depop, Vinted, Whatnot, OfferUp and Etsy with your title, price, description and photos, and you pick the category and click Post. On a phone, a copy kit walks you through each field. It does not post to those marketplaces on its own and it does not delist them for you.
How accurate are the prices?: Every price comes with a range and the sold listings behind it, each one a link to eBay, so you can check the number before you trust it. We grade the prices every week against what items actually sold for and publish the result on the accuracy page, wins and misses.

Your first scan is free with no card. Then pay as you go at $0.25 a scan, buy a 5 scan pack for $3, or pick a plan from $5 a month for 30 scans. Compare plans.