Yes, it is very easy. I made a couple of sets recently with material from spotlight that was only $2 per metre!!!
I brought, um - I think 3 mtrs ( or was it 2.5?) and had just enough for a cover and matching pillow case.
Have a google and see what the standard single size quilt/doona size is. I cant quite remember, there is a little variation from store/brand - brand, but mostly there is a standard size.
Just wash fabric first, iron. Sew hem/ends and fold over at ends. Press. Then sew each side. Then put your snaps on. Done!