I'm a tennis instructor.
A MUCH cheaper alternative, and probably more fun and beneficial, is buying a dozen green dot balls. Here's a link:
http://www.midwestsports.com/penn-control-tennis-balls/p/521930/ My neighbor is a very athletic guy but a beginner, and we have lots of fun using these balls. Actually, it's all we use when we play. The ball has less compression, and goes 75% of the speed of a normal tennis ball.
Why it's good for me: I can take full swings without feeling bad, because he will be fast enough to get to the ball and prepare for the shot.
Why it's good for him: He can take a full swing and the ball won't fly 50 feet long, since the ball is lower compression.
Why it's better than a ball machine: Not only is it way cheaper than a ball machine, but it's more realistic. Ball machines feed you with too consistent of a ball. In real tennis, every ball has a different spin, speed, depth, etc. Rallying with someone teaches you to handle a different shot each time. People who hit the ball machine too much often develop a beautiful smooth swing that turns to shit once an actual match starts:)
If we actually played a match, it would be a no contest, but if we are just rallying, it's a great experience for both of us.
Disclaimer: I have a Playmate ball machine that I use with students occasionally. Playmate is a quality brand. It was a $2500 machine owned by a club that was going out of business. I walked in, offered them $350 for it, and walked out with the machine:) It has it's place and I'll have my students use it for specific reasons, but your situation wouldn't be one of them IMO.
Good luck and have fun, tennis is a great game!
