Mobile Game Shop Help

Hi, I have a question regarding making a game shop. I need help with a system that saves currency earned in a level and persists outside of the level. Can be used to purchase items in the game shop with the game credit. This is for a mobile game.

I am using the UE4 COD Style Enemy Waves Template: ue4 cod style enemy waves template - YouTube

If there are any tutorials that already discuss this topic please post below, thank you!