You’ve gotten suggestions on where to buy, I’ll offer a few hints on WHAT to buy:
Bowls – Get stainless steel bowls. Plastic bowls can harbor bacteria, even when washed. Ceramic bowls break, especially if your dog is like one of mine that when the bowl is empty, she alerts us by flipping it over and batting it across the room.
Collars/Leashes – I love Lupine brand, they are guarenteed; even if your dog chews them up, they will replace them for free! Very helpful especially when you have a puppy! I’ve replaced several collars/leashes, they don’t give you a hard time at all, you just take the damaged collar/leash to a store that carries the brand and they swap it out no questions asked. http://lupinepet.com/
Dog food – Research the food you’re going to feed, and read the ingredients! (This goes for treats too!) Good websites to start with: http://www.dogfoodanalysis.com/dog_food_reviews/ and http://www.dogfoodproject.com/ Or if you’re interested in feeding raw, here’s a good place to start: http://www.dogster.com/forums/Raw_Food_Diet/thread/431875
Toys – Don’t go crazy buying toys, see what your dog likes first. And don’t let your dog have all the toys all the time, we rotate through toys, and when a toy comes out the dogs haven’t seen in a while, it’s more interesting to them than a toy that they’ve had for a couple months sitting on the floor.
Grooming supplies – This will depend on the breed for what types of combs/brushes you need. And get some dog shampoo, the pH is different than that of human shampoo, human shampoos can irritate a dog’s skin. Also, get a toothbrush and dog toothpate (do NOT use human toothpaste, it is toxic to dogs).
Crate – Even if you plan on letting your dog have run-of-the-house when you’re gone, still get a crate and crate-train the dog in case you need to crate at a later date. And when you take the dog anywhere in the car, the crate is the safest place. (My dogs each have 2 crates, a wire crate for their house crate and a plastic crate for the car.)