As in how much money? haha too much!
When I first started the tank I already had the tank, light fixtures, and the filter. I just had to buy rock, sand, and new bulbs, so I saved about 100 dollar that way.
I also *thought* that I wanted to keep track of everything that I spent on this tank so I would know just how much my tank is really worth. Well, I got to 400 dollars and decided that if I really wanted to look out for my well being, I would stop, and I did. I prolly have around 600 dollars invested in this tank, but it is definantly worth every penny!