Wouldn't recommend a damsel as they are aggressive towards other fish and hard to catch! I also agree go on craigslist and look for a biocube 29. Or you could buy one off of marinedepot.com new for $260 I think, then get a 30 lb bag of sand ($30), and 30 lbs of dry rock for about $60-90. I used BRS pukani dry rock and love it! Very porous and worth the money. Also I've seen good reviews on marcorocks so that's another option, and they are cheaper. That comes out to be $350-$380 and the rest can be for livestock (or/and corals b/c you would get power compact lights w/ the biocube which can grow some corals *nudge nudge*).