you can get them at amazon.com 16.95 for a 3 pack

For cheap replacement, use tennis balls or buy the cheap plastic wiffle balls and stick the fuzzy side of velcro dots to the ball. Tennis balls are a bit smaller so the arm doesn't always pick the balls up as intended.

Got this for my son's fifth birthday and it is great. I even hit balls to the kids for them to practice fielding. I am 5'3. I put it on the tallest setting. It is cool cuz the kids can hit a few balls in a row w/o having to do much. I wish it held five balls instead of three. It is a great way for kids to practice by themselves, and the sounds motivate the kids. If you buy this at walmart, and your kid doesn't like it, walmart is the best for returns. Keep your receipt, or you'll get store credit.

Height is the real limit on this toy. Kids over 45" tall, you would have to stand this on something to make it tall enough as the adjustable notches are not quite tall enough to adjust past a 4yr old's average height. It is very well balanced and sturdy so just standing it on a something works quite well.