Yeah, that would have to be almost all used eqipment. If say dry rock is 2.99/ lb, and you bought 100 lbs, you spent $300 just in rock. On top of that you need sand, skimmer (don't try to be inexspensive on this piece of equipment, it's the most important), salt mix, testing equipment, lights (a good 4ft light system will cost you over $300 new) and supplements. Not trying to discourage you, but you might need to up our budget a little. When I started my 46 bow I spent over $1000 before I put a fish in.
Are you thinking of using a sump?