Mexican is a good choice. Chicken is usually pretty cheap and you can do a million things with it. I'd go with chicken and a few sides of vegetables or rice (which I am opposed to, but people seem to love).

Grilled cheese is super cheap to make! Also, soup, dude. Make a big ole batch of clam chowder or vegetable or potato cheese soup or something and get some bread or rolls. Freeze what you don't immediately eat.