This is a very common question and the generic answer is PRICE and QUALITY.
Now I bet you are thinking "I could've worked this out by myself...Any chance of being less specific with your answer!!"
Absolutely. Here we go:
So match balls are more expensive, but why?
There are a loads of reasons why this is the case and I'll list a few for you.
Better Quality and therefore more expensive Materials used
More expensive process to make match balls e.g. thermo bonding
Most will have an extra Layer of foam on the inside of the ball
Royalties to FIFA if they have FIFA stamp of approval
To be used in Competition Matches they have to go through costly testing
So What is the price difference for a Match Ball and a training ball?
There is a lot of variables here but generally speaking Training Balls will be from $15-$30 compared to Match Balls being in the range of $30-$150.
You will end up paying a little bit extra for Custom Made Soccer Balls as they obviously don't have the economies of scale that generic Soccer Balls have.
Want a Pricelist for Custom Soccer Balls? just ask us...
whats the difference in the outside of the balls?
Training Balls need to withstand constant use over the period of a season so endurance is priority. That is why it is common for training balls to be made from PVC or PU casing as they are hard wearing and cost effective.
Match Balls are made for performance so a soft touch and responsiveness are essential. Thicker PU Covers Like PU 1.0mm or Japanese PU leathers are most popular as they give you the best touch on the ball.
How to tell the difference between a match ball and training ball?
If you look around the Valve sometimes it will say Match Ball or Training Ball. If not then look for a FIFA Stamp or IMS Logo on the ball and that is a dead giveaway that they are match balls.
Price is another indicator and a ball over $30 is most likely a Match Ball.
The stitching or lack of stitching on a ball can help you as well. Thermo Bonded Balls have no seams are fly through the air more accurately and are fully water proof. Because this is an expensive process, you'll only ever find Match Balls being thermo bonded like in the top photo.
And lastly try the kick test. Match Balls generally with have extra layers of ply on the inside of the ball or a layer of foam to give it a cushion feel. Try keeping the ball up and seeing if it has a nice cushion feel or if it is more rigid.
Good Luck with your next Soccer Ball purchase.