Let me break it down, reeeeeeeeeal propa-like, lol.
Titleist Pro V1
New: $45-$55 depending on where you buy.
Titleist Pro V1
Used: $12-$20 depending on grade
So if you buy
New Pro V1s for $50/12, each unit has a price of $4.
The average golfer loses 5 balls per round, or 1 ball every 3-4 holes. 5 balls lost @ $4/ball = $20.
So if you buy
Used Pro V1s for $20/12, each unit has a price of $1.70
5 balls lost @ $1.70/ball = $8.50
So you can lose $20 worth of balls per round or $8.50 - that's up to you!
Plus, each new ball is only hit with a driver probably twice before it's lost. (Not including wedges, irons or putters, but drivers and cart paths inflict the most damage) so if you make it through 3 holes with the same ball, you're playing with a used ball anyway.