Where do rewards come from?
The Staking Rewards on Polygon network come from two sources:
Inflation: The Polygon network allots 12% of its total supply of 10 billion tokens to fund staking rewards through inflation. Polygon has set a predetermined number of tokens to be released every year, this can be seen in their documents.
Transaction Fees: Transaction fees are collected by the protocol for every transaction on the network. The fees are shared with validators and consequently stakers.