I'll add a few sites, that are more herp related, but many have a range of products. Many of them are useful Items that you won't find at the average pet shop, or at least not at the prices here.
I have two that I always go to that weren't listed. Pet Supplies Plus carries a variety of high quality feed with little to no preservatives.
Also when you're in Houston in Texas, stop by Rocky & Maggie's Pet Shop
I love pet stores and the fuzzy/scaly/furry/slimy guys you can find in them, too! And I'm not talking about to employees!
I will also add Zooplus for those people living in Europe.
They have a domain for all the countries so select your own but my top tip is to check the prices on the other country's sites. For some reason, the German site (.de) is often a good bit cheaper than other domains. They also offer different packages and different special offers on the different domains - the German site sells Bozita tetra packs individually for instance. Delivery is free for orders over a certain threshold and a single account is valid over all the domains (so if you sign up on .co.uk, the account works fine on .ie).
They also have some own brand products which are very competitively priced for their quality. And they have a thing where you can buy a year's worth of X% discount which I've found worth it with just one cat.
