I just bought my first PCP, the Umarex Gauntlet .22 cal. It’s extremely accurate, with a 60 shot count. As for a 5 year old, it weighs over 10 lbs. I weigh 210 lbs, and getting the last few pumps into it is a chore with a hand pump. I paid $242 for the gun at SG (with joining the club, I got a discount). I bought the Umarex handpump for $131. I purchased the UTG 3-12x44mm AO SWAT Compact for $116 and another $17 for the one piece mount. It shoots pretty good with the Crosman Premier 14.3 grain Hollow Points, which are available in stores at about $9 a 500 tin. It shoots incredibly well with JSB Diablo Exact Heavy Jumbo 18.1 grains, $25 a 500 tin online. Obviously, this is not “cheap” per se, but quite inexpensive as far as venturing into the PCP realm. I’m retired, and I tend to go WAY overboard into researching a purchase such as this. The Umarex Gauntlet won every head to head challenge in the online venues, and is an excellent choice for an adult. It would be a great rifle for Dad, to teach his son to shoot with. From that angle, you could make the decision whether he is physically big enough for this rifle. It has almost no recoil, it’s very quiet- not scary to shoot. It’s cumbersome and would be impossible for him to pump up himself. Any pump gun, break barrel or PCP is going to require Dad’s help. Maybe he could be a bit more autonomous with a CO2 weapon. As a final thought, you MUST keep in mind that the Gauntlet has a regulator, which inherently makes it VERY accurate. The trigger leaves something to be desired, as well as the bolt will be hard for a 5 year old to pull back, but Dad is going to be amazed what a pellet gun can accomplish. Sorry about the length of this comment.