Our tank was ~$7-800 in glass.
Acrylic scrathes too easily and is prone to cracking with age from what I have read, some people may have differing opinions, but this was a big factor in my decision. When you undertake a project like this, you want it to be around for the long haul. Ours may end up as a sump in a year or two, but generally, when someone takes on a tank this size, they plan on it being their masterpiece, something to last them for years and years. Weigh your options carefully, this thing is going to be around for a while. This goes for things such as overflow placement and size, bracing configuration, and other configuration considerations, unless you aren't worried about money, you only get one shot at it (especially true of acrylic tanks), do it right the first time.
-Dave