You need to prune these types of job listings, they're just spam and completely unrealistic.
Solid days worth of work. Tweaking, designing, etc.
50 bucks! That's terrible. Any thoughts on how to mitigate this problem?
Personally I'd rather do something for free that benefits the general public than for someone who just seems to be a cheap bastard. Now, if it were coding for an open source project and getting payed trivial wages because the project has no money and devs just need help getting something done... maybe.