In AoTd, the currency is known as "tithes". Tithes are dropped by enemies you slay, games you complete/participate in, and by killing players. Once you have enough tithes, you can go to the "Shop vendors" forum in the "Central hub" category, there will be four known vendors. A shop vendor to purchase items from all known multiverses, a forgesmith who can be given tithes to make new items of your own design, a trade stand where you can either put items up for sell for other players or directly trade an item or even an ability to another player for tithes, and a soulsmith who grants you new abilities of your design for tithes (once a new ability is made, that counts as a level up.)