Quoted from RonSS:I'll second a Taxi like game. (Diner?)
Kid friendly, and decent ball times.
PIN*BOT stranded!
This is probably the route I'd go, unless we really need DMD graphics. Taxi offers more than meets the eye. Plays fast. Kids will get good at timing shots like the ramps and the lock on the right side and Drac on the left. Easy, fun-to-shoot ramps that can light the million-point shot, and that always feels good. Two-ball multi won't be overwhelming and is a good for them to learn how to trap up and maintain control with more than one ball in play. Spinout skillshot has always been one of my favorites, and it's a good way to teach the physics of nudging as there is no immediate threat of drain for nudging it the wrong way. Worst it can do is stop spinning and drops onto the PF. Nudging a ball around a whirlpool can really help in other games like CFTBL or White Water.
Mark Ritchie had a way of making deceptively challenging, yet universally accessible games with simple, straightforward rules. Fish Tales is another good example, though one in the condition you want will probably be on the high end of your budget.