If you can’t commit $1000+ to one of the new portable battery-powered machines, have a look at “The Twist.”
The “Tennis Twist”: Inexepensive battery-powered ball feeder.
For less than $250 the Tennis Twist offers:
Top Speed: 15 mph
Ball Capacity: 28
Ball Feed Rate: Every 5 seconds
Weight: 11 pounds
Warranty: 1 Year
If you’re looking to work purely on technique and can’t line up a hitting partner, this is a tidy little solution for you.
I’m tempted to buy one for myself to add some groundstrokes to serving practice.
Florian of onlinetennisinstruction.com demonstrates The Twist on my blog:
Buy the Tennis Twist for $229 + free shipping.
sells the unit for a fair price.