Unfortunately that's a set that seems to have been discontinued at the retail shops.

Have you thought about getting him two smaller sets instead?

What about:
http://shop.lego.com/ByTheme/Product...991&cn=356&d=9

and:
http://shop.lego.com/ByTheme/Product...741&cn=153&d=9

I think K-Mart has a sale tomorrow, and it's 40% off the second item from what I can recall. Not sure if it means you can get the cheaper of two different sets at 40% off, but might be worth trying.