This came up in our most recent game, as the group I'm GM'ing is terrible with money and has screwed up (in a fun way) almost every money-making scheme they've tried so far.
They have a very tight budget and were trying to figure out how much fuel they needed to spend to get to a certain star system, and how much fuel total the ship has, as well as how much fuel costs when they do finally need to refuel. They're flying the YT-1300 from the beginner game.
Thing is, I checked through the starship section of the core rulebook, as well as the galaxy/navigation section, and there's zero mention of fuel. Considering it's something that literally keeps everyone alive (powering the oxygen recyclers) I think this is something we should be able to reference.
I found these rules from the Saga/d6 days, and it's useful, but I'm wondering if it will work with this system, or if anyone else has created in-house rules.
http://www.rpgnet.be/resources/rules/star-wars-d20/10-starships/153-124.html