It might not be a problem in practice -- scammers may have little incentive to apply for the kinds of jobs that low-income folks would be qualified for.  Not sure what is to be gained by applying for a job that requires you to show up in person at a gas station or loading dock or whatever.

Yes. Possibly a range of titles or categories that are low income free to apply or you get 2 x free applications a month or something. Advertisers need to pay to post ads as well surely 

User21000000

econ

The big idea: Charge $1 to apply to a job (hear me out)

elvismercury

Yes, that's a drawback of this method.  There's no free lunch.