If you only want a 10 gallon it can be done for fairly cheap.... only issue is that you will have to do water changes a lot more often on it than bigger tanks, also you will have a lot more swings in water parameters than in a larger tank... In my opion if you are going to go for it, go big or go home... With a reef tank you will start small and be bit by the bug and will just go bigger and bigger. I started with a 24 gallon, went to a 34 gallon, to a 60 gallon, back to a 34 gallon, down to a 10 gallon, and then back to a 60 gallon. In the long run you will save a bunch of money if you just got straight to a 60-100 gallon tank. I will have to disagree about the statement "You won't need a filter, the live rock and sand will do that" Yes that is true but in a system that small the amount of sand and rock needed to create that biological filtration would be insane and the entire tank would be filled with sand and rock.... If you have any quetions, feel free to pm me. I have been keeping reef tanks for a good amount of time