What We Bought  - eBay listing
We picked the top used ball seller on eBay, one that advertises "High Quality", and "from indoor clubs", and says you can play tennis with them (implying most of them). We bought a box of 100 and paid $47.95 which included shipping.
What We Got  Â
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Here's what the box looked like when we first opened it. It contained 101 balls. So far, so good.
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But what was the true quality of these balls from a player's standpoint?
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Using our Grading System:Â Â Â Â Â
2 were A's - 2%
A bit disappointing, but they are "used" and we wouldn't expect full bounce.  Obviously the A grade balls have the most play left in them, and therefore are most valuable.  You probably wont be able to get them for $.48 a piece anywhere.  Too bad we had to buy 98 others to get 2.
35 were B's - 35%
OK, these are pretty good used balls, definitely playable. If all 100 were this good, I think most players would be very satisfied with their purchase. But only getting 37% of what you want is not so satisfying. If it were me I would have 2nd thoughts about spending the money next time. Better to go to 2nd-Bounces to get your money's worth. At 2nd-Bounces, when you pay for B balls you get 100% B balls.
50 were C's - 50%
This is not so good. Â Half of my purchase do not bounce the minimum standard 53"? Â
Notice the green-dot ball in there -- that is the kind of ball that was made to bounce only 50".  These would be useful for little kids starting to learn the game but now you have to sort them out.
13 were F's - 13%
These are not High Quality. Notice the brand new looking Wilson Practice ball.  It LOOKS like it has never been touched, but yet it has lost its bounce.  That is because it probably sat in a corner for years, lost it's air and dried out, but was never hit by a racquet.  Why weren't duds like this filtered out? These are certainly NOT "High Quality".
Now, don't be too hard on other online sellers. Â This is really the best they can do. Â
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It is a very tedious and error prone process to try to sort them.  Fortunately, with some high tech we've found a way to do it quickly and less painfully, and so now you can buy used tennis balls of consistent bounce quality from us, 2nd-Bounces.
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This was just one sample test, but it is typical of the online sales out there.
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So avoid the uncertainty and buy from us, because we verify the bounce of every ball we sell with our patented process. No one else is able to do this.