Coins

[Afonya619]

You do not have enough non locked coins to purchase this sale, try again in 72 hours. What is it ? And why ?

[Obnoxious]

You have to wait 72 hours before you can use Coins you got from another player (via Gifting or Trade) with another player, to reduce the damage of scams and stolen Coins. You have no such limitation with Coins you donate for or if you use them on the Store, only if they are moving between players.

[vsoe5]

They also lock coins that you donate for if you are trying to use the trade system.
If you donate you can only use the store. If you want to buy gold via trade you have to wait too unfortunately