Panniers are great and extremely useful for bicyclists. They are also extremely overpriced for a good set. I have a $250 dollar pannier set from panpack.com that is great for camping, but not so much for running around town, so i came up with the world's cheapest pannier! the total cost was only about 7 dollars and i think it looks great.
Step 1: List of Materials
Most of the materials for this project were obtained from East Bay Depot For Creative Reuse. http://www.east-bay-depot.org/ If you live in the bay area and are a DIYer, there is no reason you shouldn't be going here. I always find gems and great stuff. If you can dream it, you can find most of the supplies for REALLY cheap.
-1 Bag or Backpack. The one i chose was an old shoulder bag it was just the right size.
-1 Piece of vinyl board. I got a large piece cut to roughly the size of my bag. This gives the bag some shape and a good backing. The material is very similar to vinyl signs you find around town promoting who knows what, you could certainly get it from there.
-2 rope hooks. i got the medium sized ones. Check hardware stores for this
-4-6 screws and nuts. get ones that can fit the hole in the rope hook.
Step 2: Shape the Vinyl
First you want to shape the vinyl so it fits in the bag. i used an exacto knife and just shaped it till it fit. You can use anything you want for this.
Step 3: Prepare for Screws
Now take the vinyl out and prepare it for the screws. I measured from each edge in about 2 1/2 inches at the top and bottom to get evenly spaced holes then i drilled holes into each mark. This allows for mounting the hooks to the vinyl and the bag to the vinyl.
Step 4: Add the Hooks
Once you get holes drilled, you can put in the hooks, just make little holes in the bag where you want the screw to go, put the vinyl in and push the screw through.
Step 5: Put the Bottom Screws In
Bottom Screws will help stabilize the bag to the vinyl and make it more secure.
Step 6: Finishing Touches and RIDE!
Finishing touches involved cutting the screws with a dremel because they were too long. I also realised that my foot likes to kick the bag off when i'm biking so i put a bungee around the bag when i'm riding. The hooks on the bag hook to a back rack on your bicycle. anyway happy cycling!
hope you enjoyed this instructable!