The more experience you get, the easier it will be for you to estimate how much you'll be able to sell an item for. When you're just getting started, there are a few ways to go about it. Check the listings on sites like Craigslist, Facebook Marketplace, and eBay. You can see the list price or asking price of other similar items. Keep in mind that many things will sell for a little less than the asking price. Check the prices of sold items at eBay. After searching on eBay, you can go to the filtering options and check the box to show sold items. This way, you can see exactly how much similar things have sold for recently. Keep in mind that fees will reduce the amount you get from the sale. Learn how to sell on eBay for beginners here. When you find the right item at the right price, it's easy to profit.