I find petco to be very expensive. Especially for tanks. Their tanks are slightly cheaper than ours (maybe by $5-$10) BUT, that doesn't include the top and lights which almost doubles the price. OUr tanks all come with the top and lights!! (and, sometimes ours with the top and lights is still cheaper than the topless one at the co!) Walmart is always a little cheaper than us, but usually only a few dollars or so, and they don't have the same selection. (nor are their employees as knowledgeable). Petsmart is clearancing out a bunch of its heaters (the preset fully submersable and the Neptune heaters by Marine land, not submersible) so you can find some great deals on those! I don't know about deals at the CO, they are just too expensive for me. Oh, and petsmart will price match with petsmart.com, and some things there (fluvals for example) are much cheaper, so print out the price there, and get it matched!
Emily