I think little boys & yellow labradors were made for each other. Golden retrievers also make a good pal for a little boy. There are many breeds that go well with kids-it's important to do some research before bringing a pet home. The bigger the dog, the more they will cost to feed. (The bigger the dog...the more everything costs for them, period...) Veterinary care can be costly, (if you're considering a puppy, do NOT neglect to get it ALL of it's puppy shots. I recently had a friend lose her puppy and an older dog because she didn't realize the puppy needed a 'parvo' shot. It was so sad and totally preventable had she known.) Puppies should be tested for worms, should be spayed/neutered when they are old enough, and usually require an annual blood test/heartworm meds annually depending on where one lives...in addition to their regular adult vaccinations.
Check out the prices of pet food, (or even better check what goes into making a homemade diet for your dog) so you are aware of the cost. See if your pup is going to need to be groomed on a regular basis (nails trimmed, haircut, etc.) and get a price estimate for the breed you're interested in. Some breeds shed more than others (yellow labs, beagles, pugs, etc. can shed quite a bit).
Check out the dogs excercise requirements and temperment types. Labradors are excellent "house dogs" when trained, mine is very well behaved...her only fault is the "shedding". Some labradors can be "high strung" though and those will probably require alot of patience and perhaps some dog training classes. Labradors need alot of excercise and can be good at "running off", our local humane society always has labradors that have "ran away from home".
Not trying to "scare you", I've just seen alot of people bring home a cute puppy only to have to surrender it a few months down the road because they didn't realize what they were getting into. I've also seen people have to have their pets down for things the pet would have recovered from---if only the people had thought ahead and saved some money for unnexpected vet bills.
Do
alot of research on-line, see what health problems/diseases/ailments the breed(s) you are interested in are genetically predisposed to.
Good luck & have fun with your new dog!!