You could require people mail in their resume, which costs ~$1 within the US ($2-5 internationally depending on the applicant's location), and is a small amount of hassle without being a disproportionate burden on the applicant's time.

The on-site prior to hiring is a good idea, but I expect you might still get some spam from people applying completely blind.

> You could require people mail in their resume

That is supremely annoying for industries where applicants must average about 500+ submissions per successful job offer.

I ran across two of those last year. Great-looking jobs, too. In a fit of pique, I submitted to one with everything typewritten using an Olympia SG3, and for the other I wrote out everything longhand. With a fountain pen. In cursive. It took me nearly 3 days. I should have scanned it in for posterity, because it looked like a government treaty from the 1890s. Gorgeous, but doubtful that anyone under the age of 45 could even read it, and almost certainly that anyone under the age of 35 couldn’t. I even did a wax seal on the back fold of the envelope.

Obviously, neither produced any sort of a response, because mail-in Resumes are typical of companies that are trying to justify foreign workers. If the barriers to application are stupidly high, then of course they won’t have any domestic applications and will need to find foreign (and much cheaper) applicants.