This size ball, the smallest aside from mini-balls not used for real practices or games, weighs 10 oz. and can be used for players under 8. The No. 3 ball is only 24 inches in circumference and thus doesn't come up as high on the leg as an adult model. You don't need to provide a match-quality ball for your young player, write the authors of "The Complete Idiot's Guide to Coaching Youth Soccer."
Every four years there’s a new ball for the World Cup—and every four years players are unhappy with it. Maybe it’s too light and has too much lift, like the 2002 Fevernova. Or maybe it wobbles unexpectedly in the air, making it harder for goalies to predict its motion, like the 2006 Teamgist. Or maybe the ball suddenly changes speed, dropping out of the air and causing accidental handballs, like the 2010 Jabulani.
On the other hand, replicas (sometimes called training balls or gliders) are designed to be just like the official match balls but are much cheaper. Their panels are often stitched rather than thermally-bonded and are made of a different material. However, they’re not necessarily less durable than official match balls. So, they’re the recommended option for most players.