"I understand that $20 isn't much of anything in NYC. We are not the richest people in the world. We are just lucky enough to be able to go there. We're coming from Memphis so airfare is not cheap (not to mention hotel fees on top of that) so we really need to watch what we're spending. I've been waiting to come here my entire life so I'm not gonna not come if I can't pay for more than a bag of chips a meal. I don't want to say this to be rude. I just thought you outta know:)"
Others will have to verify this for me but I believe you could go to Carmine's and order just one entree which would put you under $20 per person. Everything there is family style so there would be plenty for two people. Only problem there is you have to make reservation way in advance.
I have not been to the Hard Rock Cafe in a few years but I believe you can get burgers, salads and a couple of other things for $20.