The amount of money that you spend on balls can vary greatly. Growing up, I almost never bought balls and just used the best that I could find. For a lot of you, that means stealing 3 or 4 out of our teaching baskets. The coaches add our used balls to them all the time, so feel free (except for the X balls – don’t take those).
If you are going to buy them, here is some information:
Standard Balls (about $2.00/can). This is what we use for high school matches. These are usually Penn or Wilson and play like new for about 60-90 minutes after you open them. Their bounce will decrease by about 20% pretty quickly. I heavily prefer Penn to Wilson – I think they are much better. You can frequently find cases of 20 cans of Penn balls at Costco for about $40 (sometimes on sale for $30 - let others know when you stumble onto this).
Premium Balls (about $3.80, or $3.30 if you buy them by the case (24 cans)). These bounce a little higher to begin with, will play pretty well for about 3 hours and lose a little less of their bounce over time. These would be Pro Penn, Wilson US Open, Prince or Dunlop Grand Prix. Again, I prefer Pro Penn. If you want to play a couple matches with the same can a few days apart, the Dunlop is a good choice. They are a little hard when you first open them, but hold their bounce over time pretty well.
New Ball on the Market (price in flux, about $96 for a case of 24 cans): Wilson Trinity - the first eco-friendly tennis ball. This ball is designed completely differently from other balls, but still plays pretty similarly. The great thing is that they only seem to go flat by playing, versus other balls that start to go flat once the can is opened. These are a great option if you want to use balls for 2-4 matches and want them to play like a new ball for all of them. These are also great for keeping in a basket for drills, serving practice....
Why play with new versus used balls? As noted, balls will lose a bit of their bounce over time. In general, that makes them a little easier to keep in play. That’s great, but every competitive match that you play (team matches, tournaments) will be played with new balls. So, switching from old to new balls (that are harder to hit in) for the matches that count puts you at a disadvantage. For the same reason, I’d also play with the standard balls instead of the premium ones (that’s what 95% of your high school matches will use).
Why play with used balls versus new balls? You will save money.
So, balance those two for yourself.
One option that is pretty good for people who want to save money on balls but still play with decent balls is to invest in a Tennis Ball Saver ($15 on Amazon). You put your balls in when done playing, twist it together to increase the air pressure inside and the balls will stay fairly decent for a few sessions (the wear on the felt will become a problem over time too).
Oh, don't buy balls online. I’ve never seen an online price for balls that is cheaper than in stores. Buy the cheaper balls at Costco if possible, or better balls Players (they just beat the online price for Wilson Trinitys by $6). I don't shot at Dick's often, but the last time I did, their prices were ridiculously high.