Well I have a pug he is 5 and he is black. I got mine from breeder. Usually dogs from pet stores are not very healthy. Hope I helped! By the. way pugs are super cuddly and love to be around people. There are good with kids and there really nice! They don't grow up to be that big but my pug is pretty chubby but that just makes cuter. I got mine when it was a puppy and he was as big as my dad's hand :)
I agree with SNA, and would add that you may even be able to find a pug puppy there. People decide they don't want a dog for lots of reasons or get surprised by a litter of puppies. If you do buy one, buy from a reputable breeder, not a pet store. Have it checked over thoroughly by a vet to make sure it's healthy.