tinfoil at the bottom of the oven (to catch crumbs) is ruining my pizzas
I would probably go ahead and get a pizza stone. Even if you don't want to bake your pizza on it, you can just keep on the floor of your oven (unless you have exposed coils/burners there, in that case, go with the lowest rack).

The pizza stone is easier to clean, and as an added bonus, it'll improve your oven by keeping a more even temperature in there.