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The scenario that keeps playing in my head is what would happen to OP's gas station if the prices go down the next day and that next day is also the time for his restocking in supplies, how can he profit if not break even.
Don't think that bitcoin will be the main payment method. It may even only attract up to 20 customers in the first few days, who then slowly return to conventional methods. Then it won't affect the OP's business too much.
Paying bitcoins for small transactions still comes with a fee, anyone would consider using it rarely.