I bought a 2010 Prius II for $19000 and they gave me $7500 on trade in for my 2004 Buick Rendezvous which every other dealership would only give me $5000. I love it so far minus the fact that im only getting 40 mpg. I figure its because I live in Wisconsin and its so cold right now.
Enjoy your new to you prius. I think this is a better deal than the 2 year older gen II. Replacing the stereo is a mod you may want to consider. I don't really average much more than 40mpg, but this depends on your trips.