You can’t directly save a single number with Play Games Services — the Saved Games API works with byte arrays. To store your coin count, just serialize the number to a string or bytes (e.g., "12345" → UTF8 bytes) and write it to the saved game. When loading, read the bytes back, decode them to a string, then parse into an integer.

So the process is:

Convert your coin count → byte[]

Save it with CommitUpdate()

On load, read byte[] → string → int