I'm getting ready to have surgery so I'm going to make a bunch of casserole's so I can portion them out in single servings and put them in the freezer to eat while I am recovering. If I package the single servings in aluminum foil is that an OK way to freeze/store them for later use?

If you are going to heat them up in the microwave, foil is not a good idea, you can't put it in the microwave, you would have to unwrap and transfer to a container. A waste of time in my book !

You have the right idea, just use zip lok containers (not the bags, the plastic containers). For chili or stew freezing, or anything that consistency, you can use the zip lok bags.

Well I don't have a ton of Tupperware so I was thinking aluminum foil and then heating it up in the toaster oven since I think u can put foil in that

Sure, that works. I've used foil and just left it out for an hour and then it peels off. In fact, if you don't have a microwave, leave it out for 3 hours so that the toaster oven doesn't burn the outside before the inside. All those dire warnings on frozen foods about 'do not defrost' are hogwash, just to protect them from people who leave them out for 10 hours in 90 degree heat.