This isn't some sort of monetary transaction. It defies the rules of economics: the price does not go up because of the demand. Rather, this is about the generosity of the spirit and being forgiven debts that we can never repay. Wouldn't we try to thank someone who paid for our meal? Hopefully, our thanks comes not out of obligation, but out of genuine gratitude and love.
More so, hopefully our thankful attitude moves us to generosity and forgiveness towards others.