Round Coins:
These give a new character "skills". Advantage is they can be used anywhere and are also used twice.
Square coin:
These include objects or texture packs for Toy Box and can be used only there.
There are a total of 20 official coins and a few rare exclusive coins. For collectors of course a dream. I had to get hold of the "lucky" with 10 packs and a coin from the Starter Set equal to all 20 coins. Otherwise, of course also makes the exchange with friends fun and sense.
I can only recommend the packs for the price!
For those who still want to wait. From 30 September there is an Amazon exclusive coin order to additionally with 3 random coins.