La Manga Club has its own petrol station, which is opposite La Plaza and there are a number of petrol stations on the motorway on the way to the airport. Unleaded petrol is Sin plomo in Spanish and diesel is gas oil.
If you rent a car most car rental companies ask for the perol tank to be returned full or they make a petrol charge, which is usually a higher rate for the petrol than you could obtain your self from a local petrol station. The best place to fill up your rental car with petrol is on the way back to the airports. There are two petrol stations about five minutes drive from La Manga Club on the motorway on the way to both Murcia and Alicante airport.