Cost really depends on what you would like in it. Initially startup cost is really where the pain point is. 10 gallon tank is a bit challenging due to the limited space for live stock. I would recommend the fluval 13 or 32.5 saltwater all in one system. I started with the 13 and upgraded 6 months later. I now have 3 tanks going! Cost on the 13 gallon after sand , live rock, heater and skimmer was about $500ish. The 32.5 was about $800. I think have my cost went into live rock on each setup. Maintenance after that is maybe $10-$20 a week between fish food, water changes and miscellaneous items needed to maintain tank.