That is a really wide swath of prices. Reefs can be delicate things and the lighting alone can be very pricey. Even the knock off lights that I usually recommend to people is about a hundred bucks. It is usually my suggestion to anyone in college who is interested in reefing is to wait. Budget aside, I had several apartments and places where I lived in college. Usually typical college student behavior until graduation, but all this moving can be stressful on the delicate corals that we like to keep.
With all of that said, a small FOWLR
system would be very doable in your current situation. Sticking with reef safe fish can be an easy stepping stone into reefing upon graduation and finding a more permanent place to live. These systems are extremely similar to what you are already running. The only difference would be that we use rock as the main biological filtration in saltwater. You'll want 1 lbs per gallon of rock. Shouldn't be an issue with someone already with their feet wet in the hobby.