Anyway, this bag is easy to make because there isn't much sewing involved. You can use the existing seams on the pillowcases. Because I wanted to make it reversible (and sturdy), I used two pillowcases I got at the thrift store. The little green patch on the front is a pocket that is just big enough for a cell phone and my keys.
Below are instructions from Martha Stewart Living that make a different pillowcase bag. From what I've seen on various blogs, this bag looks better if made of a patterned fabric. To me, the diagonal seem detracts from the whole bag and isn't as noticeable when using a patterned pillowcase. Plus, there are so many pillowcases with awesome vintage patterns on them!