If you're looking for a family friendly companion that also increases your sense of security and well being one of these puppies is perfect for you.
Their father is a Great Pyrenees, which are known for being family friendly guard dogs who often also get used to guard livestock like sheep. We chose a Great Pyrenees because we live in the country and wanted a guard dog but not one that would bite ours or our neighbors children. They're perfect for that. He's very intelligent, has learned many things, obeys most of the time, and yet doesn't require constant attention. We love him and think he's one of the best dogs we've ever had.
Their mother looks, to me, like a Mastiff Corgi (which doesn't actually exist) but her owners (my neighbor) say she's mostly terrier. Their pups look like Smooth Fox Terriers and have silky soft fur. Terriers were commonly bred to hunt, or guard. Their mother has been looking out for 4 little children for years. She too is intelligent and while not particularly trained I've noticed she is a fast learner and a likable enough dog. Her pups are super friendly, and remarkably easy going. Where many dogs are very yappy, and seem to love the sounds of their own voices, these pups are confident and remarkably quiet.
They enjoy the water, enjoy going for walks with us, or bike rides (they run along of course), and they travel well in a vehicle. They handle a 1-2 mile run quite easily. We keep them in an unused chicken yard which is about a 1/4 of the size of a typical town back yard. They have taken to that space easily providing we get them out once or twice a day for exercise and interaction. These puppies also already have some experience with cats (as we have 2) and chickens (of which we have quite a few) and they are learning to behave well around them. If you'd like them to guard your home and your son's pet gerbil (or hamster) their introduction should be supervised or else at this age they may think your son is offering them a food gift... as opposed to introducing another member of the family... which was supposed to be protected not gulped down... lol...
The reason I call them "perfect puppies" is because IF you are looking for a young pup that's intelligent, medium energy, medium size, social yet also has a guarding instinct that's clearly not hyper yappy... one of these may be perfect for you. They are only $300 each because they have not been to see a vet yet for anything. They're all healthy. They're all potentially really good dogs for someone willing to invest some time into training them. If they are left untrained, they will still make reasonably good outdoor pets with a tendency to guard you and yours as well as to eat rodents.