Make friends with the egg : ) It makes a great dinner meal.
Start with lots of things that have meat in them, and then just take the meat out - lasagna, chili, burritos, etc. Chopped mushrooms don't actually taste like that much and serve as a much healthier "hearty" option for things like tomato sauce.
Do a recipe search for beans and rice casseroles - there are a ton of good ones out there.
Polenta (cornmeal mush) is very satisfying and you can top it with an infinite variety of things.
Since you're not actually going to be vegetarian, and are just looking for ways to cheapen and make healthy dinner, don't be afraid to add a little meat to things for flavor. For example, chickpeas cooked with spinach and served over couscous? Healthy and good. Chickpeas cooked with spinach and 2 slices of bacon over couscous - healthy and really delicious.
Finally, be careful about substituting cheese for meat - while it's cheaper, it's actually less healthy. I've found that if I want something with a cheese flavor, I have the same taste if I put some right on top and brown it while baking rather than filling it through.
Good luck!