Some budget systems to consider...

All of the following systems can be had for ~$250-$300

Wave Point 4x24W T5 HO Light Fixture
Current USA SunDial 4x24W T5 HO Light Fixture w/ Timers & LED
AquaticLife 4x24 Watt T5 HO Light Fixture

For a ready to go fixture with bulbs (that I trust), it doesn't get much cheaper than these.

If you need cheaper, you may consider retro kits (as justahobby mentioned) and build a hood to place them in.

Let us know if you need further assistance, we love spending other peoples money!!!

Christopher