You can store the player data, including the coins, in a DataStore, which will persist for all the Places.
https://create.roblox.com/docs/cloud-services/data-stores
Datastores have some issues on their own, so if you want a different library (more confusing though), you should check out ProfileStore.
Either way, you just need to store coins in the datastore, and add 100 once the winner is decided. Then save their data, and you can send the players back.