I would most definately build my own system for that price. It will run much less if you buy the individual components and build a lighting system to your own specifications.
If you have some basic electrical and mechanical abilities it will no be hard at all. I made my own hood and lighting system for around $90.00 us dollars for a 40 gal. It included 4 T-8 flourecents and then I lined the light compartment with some acrylic mirror for a reflector.
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