If you're still looking for inexpensive eats for your boyfriend(? maybe it was your brother?) near Cooper Union, please refer him to the following 2 places:
1) Chickpea - on 3rd & St. Mark's - pita sandwiches filled with excellent parsley-green falafel, shredded lettuce, cubed tomato, and plenty of tahini = $2.50. Honestly, this is some of the best falafel I've ever had. They also make chicken or turkey "shawafel" which combines the falafel with some of the poultry-off-the-big-rotating-skewer. VERY tasty, very filling, only $4 + change.
2) Panya Bakery - on Stuyvesant St, where 9th & 10th Streets meet at 3rd Ave - cute little Japanese coffee & pastry shop with a wide variety of sweet and savory pastries, most only costing $1.75. And the coffee's pretty good, too.