Startup Idea : Reverse Auctioning

HiI'm planning some kind of an auction house where people (E.g. companies) can create an auction and define the amount they'd pay for creating a logo. Designers can then undercut themselves until the auction ends.Now, the things you can put on the auction house do not necessarily need to be logos and videos but can also be something like recording a rap song, proofreading, recording a song, offering SEO, and so on...