no,the petrol station is usually locked in to a contract with the supplier,who tells him what
price to sell the fuel at.when petrol discounting was happening,the station was buying at one price,then the supplier was telling them how much they would refund,to allow a lower price.the petrol station is usually only making 2 - 3 cents profit per litre,so a 40 litre fill up gives the servo 80c to a $1.20.this is why petrol stations sell so much other stuff,so they don't go broke.