I think the quality of the tank and the stand/canopy are what will dictate if that's a good deal or not. If it's a good as new rimless tank with starfire glass along with a furniture grade stand and canopy, then it's a great price. If it's a Marineland tank with some wear and the typical marineland stand and Canopy, then I'd say it's not that great a deal.
I was able to find on Craigslist a Marineland 180, stand, large acrylic sump, t5/halide light fixture, skimmer, along with an assortment of pumps, plumbing and 100 lbs of quality dry rock for $700 about 6 months ago.