We try to do meatless at least twice a week (my daughter does 7 days/wk ... she's a vegetarian, though she does eat fish). We have a meatless pasta meal, usually with a salad and some fresh-baked bread (garlic or not) once a week, and I'll throw together something like a vegetarian stroganoff with mushrooms and potatoes, or an easy mac n cheese casserole as well. Usually I make things that can be made with or without meat (like the pasta). We also like to do "breakfast for dinner" every couple of weeks, with eggs, hashed browns, and fruit salad.
The stroganoff can be elaborate (with portabello mushrooms and fingerling potatoes) or not (you can even used canned 'shrooms and chunks of the cheapest potatoes) and the McCormick stroganoff seasonings (which are often on sale and couponed). The only real expense, when I go with the cheaper produce, is the sour cream. I won't compromise on that, so I get real sour cream, but you can almost always find that on sale. Basically, slice the mushrooms and potatoes thin or chunky (depending on how long you want to take to cook 'em. Soften the mushrooms and potatoes with a chopped onion by sauteing in canola or olive oil, add the seasoning packet and water, and simmer. You can serve it with rice or noodles, if you're not being carb-conscious (potatoes + noodles are a great indulgence; my excuse is that the noodles add some protein. Again, a veg or green salad on the side, and voila! a "gourmet" dinner!
Good luck!