It's not always necessary to buy parts and accessories. Sometimes a little creativity can save you some bucks and give your ride a little style. Plastic water bottles are getting a lot of flack for taking up space in land fills, but they can also be used to keep road grime off.
On another bike I used a reflector bracket, water bottle, and hanger. For this one I drilled a hole in the water bottle cap and bolted it through the rear reflector bracket, cut the bottle in half, zip tied the two halves together to make it longer, and then gave it rigidity by giving it a metal hanger spine connected with duct tape and zip ties.
Have you repurposed water bottles for bike hacks? Let us know.