When collecting your golf equipment to go out for a round of golf you want to be absolutely sure to bring enough golf balls with you - how many would you lose this time? How sad is it to tee off with a great new golf ball and hit it straight in the shrubs to never find it back again? Wouldn't you therefore be better off with a stack of used golf balls? That depends on a couple of factors: your skills as a golfer and your aims for that round of golf.
If your aim is to practice your skills, no matter what level you're at, used golf balls are absolutely great! Practice your shots and technique over and over again with used balls, at a fraction of the cost of new ones.
On becoming more confident as a golf player start experimenting with new golf balls from a range of qualities to get a feel for the subtle differences: what happens for example when you use a ball designed for women? Or when hitting a top-end ball from a leading brand? How does this affect your play? And the time will come that you won't lose a great amount of balls anymore - which makes golfing with good quality balls that suit your game more attractive! But you'll always have a stack of used balls somewhere for those practice drills, no matter how good you are! New and used golf balls can easily be purchased online - to get the best deal for your money.
If you have no idea what to buy you can always search the internet to go through golf ball reviews.