If you want a dog that's not a lot of work, a puppy might not be the way to go. That goes doubly for a puppy bought from a pet store. No matter how many people who wander by the "display", they haven't been socialized properly. And you have to wonder what kind of "breeder" would use the services of a pet store? I mean, pet stores don't do a whole lot in the way of checks on their customers, the sale is what counts. So what does that say about the "breeder" that they're willing to hand their puppies off to these places?
Oh, sorry, slipped into a rant there.
Anyway, research some breeds then head out to your local shelter. You might come across a young dog there that will suit your needs better. Our shelter allows you to take dogs out into the run, gives an idea of their energy level at least.