I don't know how big your lawn is or how often you'd need to water but Mrs. Hippie and I decided to go "old school" at our last house (SE Idaho).
If you don't think you'll be watering often and you'd rather spend the $$ on something else (say... big TV or a trip to watch your team play at home)...
http://www.amazon.com/Sprinkler:-Nelson/dp/B0001LF7LU
I never minded using mine...
FWIW: Mine didn't cost nearly as much as the one I posted. I got it at "the Great Whore" (wal-mart).