A decent case is going to cost you around $100; if you have a system that actually needs watercooled, it really shouldn't be housed in a cheap $50 box anyway. But, yes, as long as you have room for a 240+ millimeter radiator, a pump, reservoir, and tubing, you'll be fine. Make sure it isn't made of junk sheet metal like most cheap cases, and can support the structural load of a radiator.
Or, are you referring to a closed-loop CPU cooler, like one from Corsair? If so, just about any case with a 120mm exhaust fan will be fine.