PetCo here has OUTRAGEOUS prices, so I buy everything at PetSmart. And PetSmarts are supposed to match all online prices on their website.. I've seen the policy with my own eyes.. They will not, however, match other online competitors.
PetSmarts fish dept. near me is so-so decent selection of fish/inverts but you will see at least one dead fish in every other tank, and the staff doesn't know too much about their livestock.