There is absolutely no reason not to have your own, custom made pillow cases! All you need is a strip of fabric, and ribbon or lace for detail (if you wish), and in 20 minutes you will have your own, perfect pillowcases!
Measure the width of your pillow, add 3cm to this measurement & this is the width you will cut your strip. Measure the length of your pillow, double it, add another 1/3 of this to your total and this is the length of your strip. Fold the strip, right sides together, at the length of your pillow, and then fold the extra piece back, so that the flap that the pillow will go under is formed.
If you want to add detail (ribbon, lace etc) this is when you will do it.
Now straight stitch each side seam at 1.5cm.
Overlock or zigzag the edge, folding the corner down so there is no seam showing on the outside of the pillowcase.
And you are done!!!
If your fabric has a pattern that needs to run the width of the fabric & will therefore not be wide enough to make it in one strip, simply cut each side with an added 3cm for seam & join the pieces before you fold - simple!