Are you serious? Want used ball?
I normally will change one basket full (about 75 balls) in every 2 weeks. I can sell to you then. You can send email to me for discussion - [email protected]
For brand new cheap ball, you can either go for Dunlop Power or Volkl, which is below HK20 for a can of 3. Or else, check it out from China, those Teloon is not that bad.
For cheaper price of new tennis ball, my suggestion is go to Mong Kok, buy in bulk, that is a least one box, that is 24 筒 per box. really cheaper than outside ga
This is my practice of using balls, for sets use new balls every time, then save into another basket which is used for practice.
Used tennis balls u can't buy from department stores.
However they may available from club to club or after some open public tournaments.
For example Tennis Association, South China...etc Try to contact them and good luck!
Used ball? still having air will be higher price $10 each Dunlop Fort, dead air $5 each, not dunlop fort.
Cheaper new ball can buy from China
Special price from UNY or Jusco, but still $100 for 4 cans