
I got some shade cloth, 1/2 inch PVC pipe (stay with me, here) and two copper pipe straps. Lowes sells shade cloth for a couple of dollars a linear foot, by about 5 feet wide, in a few differet colors.
First, I stitched a hem in the sides of the shade cloth so the edges wouldn't be all ratty, and then I stitched a hem in the top and bottom of the shade cloth, big enough to slide the PVC through.
Then, I cut the PVC about 2 inches longer than the width of the hemmed shade, so that I would have room to mount the shade with the pipe straps.
I hung the shade cloth on the PVC, and then put another piece of PVC through the bottom hem so that it wouldn't flap in the wind. You could also use something much thinner for the bottom, like a small wood dowel, but I had a bunch of PVC lying around so I used that (I like PVC a lot.).


You can see in this picture that the PVC continues past the shade cloth because I ended up using the PVC from the shade cloth for my patio misting system that I put in later.
The patio shade cost about $10 to make, and it took about 2 hours, because I stitched the hems by hand, and I'm not exactly a stellar seamstress...