learning to fix

So I apparently need some special tool to remove the freewheel sprocket cluster thingy. I don't know if I need some cassette thing or just a normal threaded removal tool, and so forth. I am thinking I will perhaps carry my wheel to a local store, ask what I need, and if I can buy it there. Depending on the cost of having them simply remove it for me, I might do that too. I know so little about this, it's kind of silly.