I'd want to be sure that the break(s) aren't along any of the pup's growth plates, as this could impact his/her ability to grow properly and evenly.
I'm also looking at getting a puppy soon. Personally I would need to know the "whole" story on why the puppy has a broken leg. Plus depending on what you are paying for this pup I would make sure the ...
more I think the advise to have your vet call their vet is good. I would also get in writing that the breeder will pay all cost relating to the treatment for the injury - including any future expenses -...
more and get the scoop on the leg and the treatment thus far, and the prognosis... Tough situation, good luck.