Used gas heaters can be purchased online from mass retailers such as Amazon as well as from auction sites such as eBay. Local classifieds sites like Craigslist also frequently contain listings for used gas heaters, though availability can vary based on region and time of year.
Each listing for gas heaters on Amazon contains a section that tells the buyer what other sellers have listings for the same product, including used items. For example, by clicking on the Used link below the main information block for a gas heater, users are able to view all available listings for used versions of that item. These listings contain details about the product's condition, the base price, the shipping cost, delivery options and a summary of the seller's feedback over a 12-month period.
Users are also able to view seller ratings on eBay. Each time a customer buys a product from a seller, he has the option to rate and review the experience. This feedback is the best way for site users to judge the trustworthiness of a seller before making a purchase.
Craigslist does not contain seller ratings in its postings because it does not require users to create an account in order to post on the site.