From doing research, it looks like Automotive Parts and Electronics are the best items to sell on eBay as they are the most popular. Why we think it's the most popular is because people are always needing new replacement items under theses two categories. Small items in the Automotive category like Hubcaps, Window Switches, Climate Controls and other items in this category, seem to sell fast on eBay and they are the easiest to ship.
When selling, make sure to find a product that you can find cheap and that you can make a good profit from. Junk yards are a great place to get car parts from because they want to sell parts fast, and people can get a good deal from there. It's important to have a partner when going to junk yards, so that way you'll be able to find more car parts as you walk around inside the junkyard. If your lucky enough, some junk yards can actually test items to see if they work.
By posting items online under the Automotive Category, you can save people a trip to the junk yard, but it may take a little longer to receive a item because of shipping. Some Junk Yard businesses themselves are actually posting items online as a way to make extra money. The more you sell, the better the profit will be. Anyways, hope this helps and to get a discussion going, What items do you think sell fast on eBay and give a good profit?
