Purchase Supporter Credits in game! These can be accessed by clicking the bug in your inventory.
Each dollar spent is equal to 100 Supporter Credits, meaning if you spend $10 you get 1,000 Supporter Credits.

This can be redeemed for things, such as:

VIP - 1,500 Supporter Credits
VIP+ - 3,000 Supporter Credits
MVP - 6,000 Supporter Credits

10,000 IC - 1,000 Supporter Credits