I also live with my meat-lovin' boy who is open to vego food, and we are also on a college budget.
My boy lurrrrrves beans. Loves them. Will have them with everything. Dried ones or out of a can. They fill him up, too. He's a big fan of bean-based stews, or bean-based taco/ burrito filling.
Hm...what else? Eh, he's happy with pasta + vegie sauce + cheese (he has no problem with having beans in the pasta sauce, by the way).
Roast veges + a vegie THING go down okay. Tonight is little pumpkins stuffed with couscous and veges and cheese, with roast veges on the side. Like meat + 3 veg, but with a fancy veg instead of meat
We've got a mock-meat 'roast' in the fridge to try soon too.
Burgers with a baked field mushroom instead of a meat pattie are super good.
DIY pizzas on pita bread - like paper-thin sliced pumkpin/ sweet potato on mine, with zucchini and olives and mushrooms. This is also an easy way for him to have a meat-eating night. He can just add whatever meat he wants to his pizza.
Coconut milk based curries (fattier but more filling) with root veges and lentils are good. With rice on the side.
On a really desperate night I'll make a pile of mashed potato, steamed carrots and peas, and fried onion and mushroom mixed through gravy poured over the potatos.
Oh! Or vege stacks! (boy wooed me with these when we first started going out). Cut lots of veges (potatoes, sweet potato, carrot, zucchini, capsicum, pumpkin, whatever) into 1cm thick (uh... 1/3 inch?) slices crossways. Roast until cooked through. Arrange in a stack on the plate, and garnish with pickled asparagus and mayonnaise (no idea where the garnish and mayo comes from, but he insists on it every time, and it is kind of yum).