Many clients are not sure which pet store has the best items, but I've been to them all and can help point you in the right direction.
For online shopping, PetFlow is my favorite. They collaborated with Zak George to support training without pain, so you should not find any products on there that would be detrimental to training. They have free shipping over $49 and a great "under $5" section for pups that go through stuffy toys in short order. Remember what I always say: stuffies are like your beverage of choice, e.g. lattes or martinis. They are pricey and not meant to be around forever, but fun while they last.
For in-store shopping, Petco is my top choice. They have pledged to get rid of shock collar products which is a huge step for dog welfare. They also have the best selection of interactive toys including puzzle feeders that your dog will love.
Smaller shops in our area that you may like if you aren't near a Petco include Loyal Companion - they stock the Ruffwear Front Range Harness that I like if you want to see one in person.