I get always confused with that. What am I suppose to use for what and where (US English / UK English?)
I need "gas / petrol / benzine / gasoline" for my car.
Gas is the US term for the fuel put in cars; the Brits call it petrol.
Gasoline is the full word that gas is shortened from, but no one is likely to say "I need to put some gasoline in my car" (though we would be likely to say "Your garage smells like gasoline!" in the US. When it's being put into a car it's gas; when it's being discussed in any other way it's most often gasoline).
I've never heard benzine used in reference to car fuel. In fact before looking it up just now, I'd only ever heard it in reference to its use in sodas! I don't think anyone uses benzine to describe car fuel. Suffice it to say that if you use gas or petrol, depending on your location, you will be perfectly well understood.
"I need "Gas / Petrol / Benzine / Gasoline" for my car."
In AmE, "I need gas for my car" refers to gasoline that you would buy at a gas station.
But "I need gas for my stove," or "I need gas for my heater (or furnace)" refers to natural gas that is usually piped into your home by a utility company.
You generally wouldn't say "gasoline" or "natural gas" in informal speech, unless it were needed to clarify which kind of gas you were talking about:
"They threw gasoline onto the wood stacked up for the bonfire."
"The natural gas plant is a few miles from town."
"After paying my gas bill, I had just enough money left over to put gas in the car."
If you need petrol for your car, you're someplace where they speak British English.
If you need benzine/benzene for your car, I'm pretty sure you're speaking something other than American or British English.
Gas is short for gasoline. You can also put "gas" into your car that is not gasoline, for instance liquid petroleum gas which, here in Australia is very popular (and cheap) which is actually gaseous. When people say "fill my car with gas", I instantly think they mean LPG. I think that petrol is a much more satisfactory word, due to the fact that gas can mean something completely different (as an end result). All of it really comes from petroleum anyway, (just refined).
I can remember as a young child growing up in New Zealand in the fifties, hearing the word benzine being used as a word for petrol. As in, "I'm going to the garage to put some Benzine in my car". Then again, as a child, I could have misinterpreted what was being talked about. There were many different grades of petrol as well as many additives.