1 Bottle Cap
1 3/4" long 1/4"-20 Screw (usually where you find locks and door knobs)
1 1/4"-20 Nut (usually where you find locks and door knobs)
2 1/2L Flat Faucet Washer (usually near plumbing with sinks and faucets)
1/4" Drill Bit
1/8" Drill Bit
Find a bottle cap you want to use. Mark the center. Use the smaller 1/8" drill bit to make a pilot hole. I use a big cardboard box so I don't worry about making holes on my workbench. Then expand the hole with the 1/4" drill bit. Clean out the center.
Take the 3/4" 1/4-20 screw then thread the nut through to the base. Take one of the 1/2L washers (O.D. 25/32") and thread the screw into it. The inner diameter of the washer is smaller than the screw. So you may have to set it down a table and screw down with the screw driver. Then it's a matter of hold the washer as you screw it flush against the nut. Take the screw-nut-washer piece and thread that though the bottom of the bottle cap. Once completely through, thread it into the second washer. Both washers should hold the cap tight. This way you can thread the entire thing. You might want to use a third washer or some other spacer depending on how shallow the mount screw is on your camera.
Fill the bottle with some sort or fluid or sand. Anything that will give it weight and keeps the bottle pointing to the ground would do. Then you've got a cheap stabilizer. If the bottle cap is common enough (like from bottled water or soda) you don't have to bring the body with you. Just buy your drink wherever you are and thread your camera in. You might get some looks but who cares if it makes your camera more stable.