There are 3 things you should never skimp on; lighting, filter, and skimmer.
Here is my 90g setup.
Lighting- Lunar Aqualight 48"- $250
Filter- Tidepool II w/quiet one 3000 pump-$200
Skimmer- Nautilius- $170
Youshould definately get a wet/dry filter. It will be possible to get away with...