If you'd like to try this, you can use any fabric -just cut two squares the size of the pillow form that you want to use, plus 1" to allow for 1/2" seams. To add an invisible zipper, place the right side of the zipper down onto the right side of the fabric, centering it on one side. If you can't find a perfect match for the zipper, don't worry. With an invisible zipper, all you end up seeing is the zipper pull.
Then sew the other side of the zipper right side down on the right side of the other piece of fabric, so it looks like this:
Open the zipper at least halfway. Then sew together the remaining open sides. Why open the zipper before you sew? Because if you don't, you won't be able to turn the pillow right side out!
I used pinking shears on the edges because I was a feeling too lazy to change my serger thread color. You will want to finish the raw edges of the seams in some way. Notice how I clipped the corners at an angle- this will help you to get a better point on the corners when you turn the cover right side out.
Now, just give the cover a nice pressing, insert your pillow form, and zip it up!
You can change the cover when the season is over, and store it away until next year.
So, for under $10, I got three new pillows and one new tablecloth to spruce up the house for summer! I don't always save money when I sew, but I think that if I had purchased these at a Pottery Barn, I would have probably over $200 for the whole set. And this didn't even take that long! Maybe two hours tops.
The store that I got this at was Hancock fabrics, so if you have one near you, check out their table of home dec flat folds and be sure to take your 50% off a cut of fabric coupon. They have so many cute remnants right now.