An average driver, buying 40 litres of unleaded petrol weekly, could save up to €416 yearly depending what part of the country they live in.
The differential in Munster is as high as 20 cent per litre.
Until this week's surge in the price of crude oil, prices at the pumps had been remarkably stable over the past 12 months.
But significant price differentials are creeping in at service stations countywide.
The average price per litre of unleaded petrol was 90 cent at the end of April but has increased in the past two weeks to 93 cent.
The threat of €1 per litre is just around the corner.
However, prices here are about midway in the league of rates in the euro zone.
From a lowly 80 cent per litre of unleaded in Greece, Dutch motorists are paying €1.21 per litre.
Belgium, Finland, Italy and France have already breached the €1 barrier while the average price in Denmark, outside the EU, converts at €1.17.
Spare a thought also for motorists in the North, where unleaded trades at €1.16 per litre and diesel at €1.19.
Other EU countries where the price remains below the Irish average of 90 cent are Austria, Luxemburg and Spain (82 cent).
The AA's advice for petrol buyers is:
Get to know the prices in your area as rates will rotate around the average by as much as 5 cent per litre.
Always favour the garages with the cheapest fuel rather than staying loyal to one outlet or brand.
Buy petrol in units of litres rather than in units of price.
Ignore loyalty schemes, bonus schemes and just concentrate on price.