Petrol station owners have explained the profit they claim to make after a customer complained about the price of fuel.
The average price for a litre of petrol hit a new record high of 185.04p on Sunday, in further misery for drivers.
The average price of diesel was 190.92p per litre, having fallen slightly back from a record of 191.03p on Saturday.
It comes after the price of filling up a 55-litre family car hit the £100 threshold on Thursday last week.
One petrol station recently posted on Facebook about an exchange with a customer who despaired at the sky-high prices, reports Wales Online.
Are you worried about the rising price of fuel? Let us know how it is affecting you: mirror.money.saving@mirror.co.uk
The Brian Llewelyn A'i Ferched garage at Eglwyswrw, Pembrokeshire, said: "Tonight we had one customer turn up after we had put the pole signs off, as we were closing.
"This person pulled up to the pump, saw it was 193.9p per litre. They came into the shop and said, 'I was going to put fuel in but not at that price’.
"I said, 'I'm sorry, but it's not my fault'. For everyone that is thinking that it is the petrol forecourt themselves that are making the money at the moment, here’s a quick breakdown of how little forecourts actually make from the price of fuel."
The business explained that a £100 sale of diesel at 193.9p per litre accounted for 51.57 litres of diesel - with a 4p-per-litre profit that leaves £2.06 for the filling station.
The garage then claimed that if the £100 is paid using a credit card, the card firm charges £1.69 in interest for the transaction.
That would leave the garage with 37p — and that is before taking out overheads such as electricity, maintenance and wages.
A similar rundown was shared by the Gulf Tanerdy Garage, a family-run petrol station on the edge of Carmarthen.
They posted on Facebook: "Whilst as a local business we totally understand the frustrations with all the price increases, ESPECIALLY the fuel that helps you get to and fro, we have given you an honest breakdown of your spend on petrol/diesel.
"Of £50 that you spend on fuel at Tanerdy or Gwalia this week we forward the following: Tax (fuel duty): £13.94. Tax (VAT): £8.33. Gulf: £26.35. Total £48.62.
"We keep £1.38 to pay rates, energy costs, wages, national insurance, pension contributions etc."
The surging prices have led to concerns from the Government that the 5p cut in fuel duty isn't being passed on to customers - but petrol stations are blaming rising wholesale costs.
The competition watchdog, the Competition and Markets Authority, has now launched a review of the fuel market to see if the 5p fuel duty cut is being passed on.
The Petrol Retailers Association said members were operating on "razor thin margins".
The Mirror recently broke down the price of what you're paying at the pumps, and where that money is really going.
