Personally, I think it's a pretty good deal. I think the lights are fairly lame but outside of that sure. I'd try to reduce it by $50 to $100....$300 would be legit I think.
LOL....$1 per gallon is petco territory, not hobbiest and they are never drilled for that price. Stand free? Never....they don't come free with the tank and shouldn't expect to be given away. Sump for $20? Try telling that to ANY LFS....more like $200. $40 for a 40g bowfront, unlikely.
Not trying to be a turd, but this statement would be very unrealistic in my house. Maybe for a freshwater set up but absolutely not for a reef tank. Yes, deals like that come around from time to time....but so do $1500 50g set ups.