Binky,
Sounds like you are in the same boat as I was last summer.
Prior to joining Ecomodder I used to fill up a little at a time when I had the money too (and since US fuel was $3-4 a gallon I was only grabbing a couple gallons at a time). After joining Ecomodder I saved enough money over a week or two to put a full tank in (so I could accurately track my tanks) and then instead of filling up a few times with a few gallons I put a 5, 10, 15 bucks in an envelope in my car every few days and by the end of the tank I had enough to buy another full tank. I figured if I had enough money to put a couple gallons in every few days I'd have enough money saved up by the end of the tank to fill it completely. It took a little patience not to spend the money in the envelope but it gave me a full tanks worth of info. and paid off in the long run. Sometimes I even had a few bucks left over in the envelope after filling up to treat myself to a beer on Friday!
