Don't rule out VHO or T5's if your getting a BTA...but anything more complex I would definately go with a MH...I have scored MH setups for far less than 300...I by used ballast and capacitor, pick up a reflector and a socket, then buy a new bulb, and put it all in a DIY box...then again I'm pretty decent with electronics, but there are site out there that will walk you through it if you google a DIY MH setup.
Don't forget, just as important as lighting, current, food, water parameters etc...