Thats a very good deal. I built mine, basically the same setup but also got lines, two perlicks, and two ball lock cornies for $500 (everything included). Plus I had a lot of fun in making it and a little extra pride than buying one prebuilt.
If you don't have some basic tools to do the conversion, like a drill and bits, sander, hacksaw, etc., than you might not be saving money by building your own.
(~):} Just a little Furthur (~):}