What is the ruling on selling "Ludo Star" money and "FIFA" coins? Is it forbidden?

The ruling on selling or buying what is used to charge games like Ludo Star and FIFA depends on the ruling of these games themselves.

Games become forbidden, and it is forbidden to sell what upgrades them or aids in playing them, if they are associated with forbidden things such as gambling, betting, explicit images, music, promoting forbidden acts, corrupt beliefs, or inciting immorality.

However, if the game is free from these forbidden elements and similar things, there is no harm in buying it and spending money on upgrading it, though refraining from all of that is more preferable.