One of the comments above reminded me, my very first quilt ever I used a black bed sheet to back it with, I couldn't afford to by backing fabric. It's still going strong, that quilt, my son drags it around with him, and it's been through the wash a number of times.
Thank you for the offers to go shopping! :-) I hadn't thought of that, and it's a really good idea. I set up a paypal account when I bought off ebay, which makes things easier. The websites are all cool, but unless it's a print or a certain type of fabric you're looking for, it's hard to know how "real" the colours are.
I will be in touch! :-)