That looks like a nice system. You could definitely do the same amount of water cheaper by using home depot racks and normal glass 20 gals (esp during Petco's sale, which is on right now)
But those look like acrylic tanks, and seems like they are rigged together somehow and contain some equipment. I would try to talk the price down a little bit. But it does look like a nicer setup than the one I described above (depending on the equip)