I'll just tell you what I know from having my pup. He's 5.5 m/o now and we got him at 8 wks. He's a dachshund mix, was a little under 4 lbs when we brought him home, and about 13 lbs now.
1. Does anyone know how much petsmart/petco training costs? are they any good?
I think it's around $120? for 6 classes. I went with a local trainer whose career is dog training. I just felt uneasy about who, exactly, was training at Petsmart. Puppy classes with her were $140 for 6 wks, which I remember being a little more than Petsmart. He's now in Good Behaviors II, which was $150 for 6 wks.
2. How many times should my puppy be fed daily? right now he eat purina puppy chow (watered down so it is softer)
Mine was getting 1/4 cup of puppy chow 2X/day when we brought him home. Then the vet said to increase it to 3X/day which we've been doing ever since -- only we started weaning him off puppy chow a week after we got him (left him on it the first week to give him time to adjust to new stressors before changing his food) and he's been eating Chicken Soup for the Puppy Lover's Soul 1/4 cup 3X/day. He could eat more, but we're training him so he gets LOTS and LOTS of treats (which are actually often just pieces of kibble), so we underfeed a bit so he doesn't get too many calories from the extras. He didn't need his food soft ever though. He just chomped it down.
3. How much exercise does an 8 week old puppy need?
Just go with what the puppy wants to do. At 8 wks, Hamilton would run around like a crazy maniac for 15-20 minutes, then pass out for 2 hrs. Now he likes about an hour of crazy time every day, and is otherwise relatively mellow. He's unusually calm for a puppy though, I think, based on other pups I've met since having him.
4. My puppy has already been dewormed and given a flea treatment recently, but my vet that I am going to tomorrow tells me I have to give him another flea treatment and deworming, is this going to be to much for him? (he doesnt have worms I checked his poo)
You can't see worm eggs or things like giardia and coccidia in the poop. You should bring in a stool sample for the vet to check, and if THEY don't find anything, then he doesn't need to be dewormed again. What flea treatment did he get? If it was Frontline/Advantage type stuff, then he needs it once a month. If it was something like a capstar, that only lasts 24 hrs. He should be on monthly flea prevention and monthly heartworm pills.
5. What is the best puppy chew/ puppy treats? for when he is teething or whatever
The best is whichever one your puppy likes to chew on. Mine has gone through phases of what he likes. We didn't give him edable chewies for a few months after we got him because we didn't want them to upset his stomach. Now he loves compressed rawhide, and other edables like greenies and filled bones (supervise these to make sure pieces don't come off). He's never liked kongs for chewing but he likes them when they're filled. He likes softer rubber chewies, and things with nubs. He likes canvas type stuffed toys too. And rope toys. The key was just always having a toy in your hand when he was younger to jam in his mouth when he started getting bitey.
ETA: Check your dog toys often!! If they're coming apart, breaking, pieces are coming off, GAME OVER! Take 'em away. My puppy also adores plastic bottles, peanut butter jars, and empty yogurt cups -- but he has to be watched closely with them for when he starts tearing the plastic apart.