screw remaining shown at bottom of pic

So I want to repair my fancy-pants pair of sunglasses that lost the tiny hex-screws that hold the lenses on. I googled for repair screws/nuts and found these on eBay:

The kit is $0.99 with free shipping. How can that be? I mean, that’s a loss proposition for any business, isn’t it? Although I guess I have only a dollar to lose finding out.

Or I can pay $18.95 processing fee to get replacements via the manufacturer’s lifetime warranty (which is less than the cost of a whole new pair to them and so just another way to make $ out of me).