There are plenty of restaurants. There are some popular chains, as well as some good non-chain places. But yes, you are more than welcome to eat on campus! You can pay cash, or you can get an off-campus meal plan! You can find information about it by following this link.
http://hospitality.mcmaster. ca/mea...offcampus.html
Eating on campus would definitely be a lot cheaper than eating at restaurants all the time.
Also, keep in mind that there are lots of things you can get at grocery stores that don't require cooking. There are plenty of TV dinners, frozen meats, fresh things available. All you'd have to do is turn on the oven and maybe eat some cold veggies or a simple salad on the side.