Gas, as I grew up calling it, is usually called petrol here, sometimes fuel. My friend Christine has a VW Passat and she has to put Premium fuel in her car and I couldn't for the life of me understand why.....until I moved to Australia. In the US the "regular" gas is only 87 octane and "premium" is 91, whereas in Germany 91 octane is actually hard to find where they primarily have 95 octane, which is why Americans must use premium fuel to drive their higher-end German cars. The engines were built to use the richer fuels. In Australia "regular" gas is 91 octane, so if I bought a Passat I wouldn't have to use premium fuel, premium fuel here is 98 octane and there are a few stations that actually sell 100 octane. Right now Costco is selling 91 octane at $1.38 a litre ($5.31gal), 98 octane $1.52 a litre ($5.85gal) and diesel $1.47 a litre ($5.65gal), all the other stations, Shell, Caltex (which I think is part Texaco),BP, 7-11(which sell Mobil) are all a lot more expensive, by the way Costco is supplied by Mobil fuel also, which was my fuel of choice when I lived in NY.
I was actually curious about the fuel here, as we have Shell, BP and 7-11 which was available in the US. Caltex I had never heard of before but their symbol kind of resembles the Texaco logo, so who knows. There are also independent gas stations, such as Matilda and Freedom, each individually owned. Caltex is owned by Woolworth's Limited, Shell is owned by Wesfarmers who separately are the duopoly that owns all Woolworth's (Woolies for short) and Coles supermarkets in Australia. Here in Australia those are your choices for supermarkets, they also own the bottle shops, the only places you can buy piss (slang for beer) :D - or any other type of alcoholic beverage, they also own the majority of the bars in Australia, if you see a certain bottle shop, next to a pub, then they own the shop and the bar. Coles owns Bunnings, which reminds me so much of Home Depot that I often call it Home Depot, funny thing Woolies owns Masters, which is part owned by Lowes in the States. I so much prefer Masters as it is air-conditioned and has a lot more appliances. It's also marketed towards women as we are the ones who say what art and colours go in our homes. :) (Bunnings has many oscillating fans to "cool" the warehouse and it's stinky in there - imagine fertilizers and such).
There is also Aldi and IGA, short for Independent Grocers of Australia and now FINALLY Costco, so the duopoly can shiver in their knickers a bit, competition is excellent for the consumer.