Weetsale (www.weetsale.com) is the platform that lets you know what people are selling on Twitter. Using the search engine, you can find what you want, and contact the seller through Twitter. It is also very useful, simple, and free for sellers. The only thing you have to do is taking a photo of what you want to sell, tweet it with #weetsale, and it will automatically enter our file of products.
Besides, a profile including all the things you go tweeting will be created, and this will be associated to your Twitter account.