Is this an example of a function and non-function?

Is this an example of a function and non-function? I go play bingo every Tuesday night and it cost $100 for 16 cards to potentially win a jackpot of $5,000. So this would be a function because every Tuesday night the entrance fee and jackpot are the same. It would be safe to assume that if I go play on Saturday then it would cost the same however the cost is $150 for the same jackpot but because the night is different it cost more to play.