I am guessing the 2 sheets of acrylic were around $700 each, about $150 in 1/2" square, about $80 for the sheet of ABS and another $60 for the solvents. So about $1690 to build that tank yourself. These are just guesses on price and like the OP said, prices very greatly depending on location. There is a guy in Chicago (can not think of his name) that quoted me a 600g acrylic tank for about $3000 and when I priced the material to do it myself it was about half his cost, so depending on your acrylic "hook up", I bet my price is pretty close. The dimensions of the tank I was pricing was a bit different though.
Very nice tank and build BTW.