I don't keep track of how much I spend on my tank. Don't want to know.
However, I did get the tank, stand, filter, heater, powerhead, lr, ls, some tests and some coral from my mom when she upgraded to a bigger tank -- so thanks to her, my wallet is considerably heavier. She also got me my Coralife 50/50 96w lighting as a "welcome to saltwater" present. So I got to spend most of the money on the fun stuff -- corals and fish. Other than that, I've upgraded the heater and powerhead, and now use the others for water changes (which I have to do religiously, since it's a 10 gallon). Really, the only expenses I have now are upkeep, since I have all the equipment, corals, and fish. Finally.