You've received a load of great advice so far.
I'd like to add one.
Check out your local library. Often they will have "basics" of sewing books, and even some "all about quilting" type books. Some may be a bit old, but the only real thing that's changed in the past 10 years is the use of a rotary cutter rather than scissors for cutting.
The rest is variations of the same thing. Joining pieces together to make a pleasing pattern, adding a layer of batting and a back and sew them together - either by hand or by machine, or even by tying them with wool every 4" or so.
To save money while you're learning, you can even use "cheater" batting. Just pick up the prequilted fabric (usually in baby section), especially if it's on sale. Use that for your practise quilts and save the expensive stuff for when you're more confident. Even an old flannel blanket will work for batting. If you're going to machine quilt, I'd suggest spray basting your layers together, and to stay away from polyester batting as it shifts a lot more than wool or cotton.
And shop around. Some places are a LOT cheaper than others.
It is always worth it to take classes. Even the "experts" still take classes.
And don't forget to have FUN!