I'm guessing he's planning the 55 in his sig... you should be able to do it if you get cheap plants... and use cheap substrate like sand or even if you used a mix of something nice like eco complete and cheap gravel or sand, a hundred bucks will do you. buy things that grow fast, and maybe start a hair lighter than you want. I've had a lot of success with dwarf sags growing fast... and they were maybe 4 bucks each at a premium price store. bulbs are almost free. I got a multipack at petco for maybe 4 bucks that took some time, but generated enough plants to practically clog 20 gallons. some nice ones too, a madagascar lace, etc. avoid the more expensive specialties and harder to grow ones...