Has anyone ever won the amazon contest?

I've won quite a bit in gift cards via the promotion challenges Rover holds. This most recent sweepstakes is the first one (since I started) that you aren't necessarily guaranteed a win if you participate.

If you're referring to the most recent one, done as a sweepstakes, that winner wasn't announced yet.

As for past contests, yes, lots of sitters have been awarded money by Rover to spend at Amazon or other retailers. The best suggestion I can give you for contests where you can see points needed to qualify is to review how many points you earn for each entry category, the requirements including how often, and create a routine to promote your Rover services. From your dashboard, you can even track your entries.