Hm... adding up fish costs... yeah, I don't even want to do that. I have six tanks running right now and a total of eleven bettas (8 girls, 3 boys). Rough estimate? Ah... probably around $300 thus far. One of my smaller tanks was free as we had it in the basement. Everything else cost money, though. Gravels, sand, plants, decor, filters, replacement bulbs, even the bettas themselves (some of them were pretty pricey considering I like some of the more expensive tail types).
I'm afraid if I actually add this all up, I'm gonna be higher than I think, and... yeah, I don't wanna think about it. My fish make me happy, but I'm not in the very best of financial situations right now, so... it's debatable whether spending all the money on fish was the best decision for me. But it's spent and I love my fish, so no big.