The guppies you buy from a big mailorder place like petsolutions or Foster/Smith are going to be the same crappy guppies you'd find anywhere else, and thusly not worth the trouble & expense. If you want good guppies worth having, and I'm assuming that you do since you don't like your local ones, then go to aquabid.com and peruse the numerous selections available. They're expensive, but they're show quality fish which are good for breeding and for selling to local stores.
There are a few good guys in the guppy section, and some very bad ones, too.
I can't say openly here which are which for liability reasons, but Aquabid has a feedback forum. Just click "forums" at the bottom of the main page and then go to the feedback forum and either have a look around or make a post asking who is good & who is bad, and you'll get your answer pretty quick. I'll give you the info myself in that forum.