Price on the 90 kind of depends on what's included. Here's some of what I have: 90g tank with internal corner overflow including standpipe, custom wood stand and hood (cherry type color) with small flourescent fixture in the cabinet, 48" light fixture with 2x175 watt MH + 4x35 watt (?) PC, Kent Nautilus TE skimmer or Seaclone, Red Sea wavemaker, 20g tank for sump, couple heaters, prolly have a couple MaxiJet powerheads and MagDrive pumps, electric feeder (for flake or pellet), and some other miscellaneous stuff.
$900 takes it all. The light fixture alone cost more than this!