If you're serious about this idea, you should run it by some of your friends/ co-workers that you respect. If they seem excited by it, continue to develop the i

If you're serious about this idea, you should run it by some of your friends/ co-workers that you respect. If they seem excited by it, continue to develop the idea with them and bounce ideas off them. Once you gather a group of people that work well together and have a general understanding of the problem/solution, start building an MVP. Competing with Amazon, Ebay, Craigslist, etc is extremely difficult because of positive network effects. Building a product to compete with the bigs guys is going to require an enormous amount of effort and a team that seriously believes in the product. If this is something you're set on gather a small team and get to building and tweaking. You may find that your competitive advantage doesn't exist, but you may also find that you can deliver in a way/space that the big guys can't. The key, however, is to get to building and chasing down users like there's nothing else that matters. Like others on here have said ideas are a dime a dozen, so just get to building.