I cant speak for petsmart specifically, but i do know that a lot of places will not price match their website, because some places adjust their online prices to make up for shipping and such.
I did it at Petsmart with silver dollars just recently. Their online site showed $1 each but said "in-store only" on the site as you can't have fish shipped to you from their site that I know of. When I went there they still showed $4.29 each. I pulled it up on my smart phone for them to see and they gave the $1 each price...then honored a discount coupon I had that gave 30% off. $0.70 silver dollars = win!