Bob give a great perspective. To add to it, as Bob has done, you can put some flooring right on the concrete. You have to assume 2 things right off: 1) you don't have a moisture problem where the basement is damp/humid due to moisture coming from under the floor, and 2) the floor you want doesn't require a sub-floor (like a wood floor would).
One other thing to check out is what will your insurance company pay for should your pipes break. (Assuming you don't qualify for flood insurance.) My insurer will only pay for items like the hot water heater, the washer/dryer, the HVAC unit, the extra frig/freezer, etc., etc.. They WON'T pay for anything else stored down there. I don't know if they happen to distinguish between finished rooms in your case or unfinished ones as is mine. DO check it out anyway. This may have an impact on how much you want to spend on flooring or anything else.