Good for you! I had been quilting all the time for years and one day realized all my own quilts were in tatters, and that I too was "quilt worthy". I have a goal to have a different themed quilt for each month of the year, but I'm not all the way there yet.
As Susie mentioned, you can cut your own squares as well. Fabric is usually good for 40" across but is sometimes tight when you include white/printed selvedges. If you are buying yardage for them, 1/2 yard isn't such a good size, 18" has a lot of waste but 2/3" yard pieces (24") give you variety (in my opinion) enough room without too much waste/extra cost.