I am sure Ray will bring you years of enjoyment but it sounds like you got ripped off BIG time...at this point I would not trust that they did any shots etc. that they said they did..helk if I where you I would probably be in small claims court with the breeder. I would get the pup checked for worms, the breeders seem like sum.
As far as food is concerned, since it is a pup they tend to eat more than adults but also what are you feeding him...The lower quality of food the the more they eat poop, too. Quality foods are about the same price as the grocery store stuff, I feed mine Nature's Recipe it is only $26 for a 40lb bag. You do not have to buy it as frequently either so in the long run it could be cheaper....( I am not saying that you feed your dog poor quality food I am just saying this ,in case)