With these type of operations it becomes a bit semantic and depends entirely on how you define costs and over what timespan.
You have to ship it there via tanker, store at McMurdo, and ship across the ice on special purpose vehicles. If you divide the whole cost of all that up per gallon of fuel you get a price. But if you need more, the margin cost for the next gallon is going to be an interesting one, and probably come with a free extra 9999 gallons or something.
roughly $3 dollars per gallon purchase price for 5-6 million gallons. Plus tanker costs to McM at between $25k-$70k per day for roughly 90 days. Plus the cost of the ice breaker, between $3.5-$11 million per year. [0]
That's just to get it to McM and doesn't include the labor costs of the fuelies based in McM. Then you gotta get it to Pole, which is a combination of the overland traverse and lc130 tanker missions.
[0] https://erdc-library.erdc.dren.mil/jspui/bitstream/11681/243...