Record clamps help level and stabilize records on the turntable platter. They usually run $25 and up. This instructable shows how to make one for a dollar.
Step 1: Obtain a Hockey Puck
Pick up a hockey puck with standard weight.
Step 2: Find the Center
Use a caliper and compass to find the center of the puck. Mark the spot.
Step 3: Drill
Drill the center through with a small drill bit and redrill the hole with larger bits until the hole accommodates the spindle on your turntable.
Step 4: Set on Record
At this point you could add metal to the puck to increase weight, but I find the compression sufficient. You could also paint the puck or add a bullseye level to the center for a few dollar.
Step 5: Play a Record
Place the record weight on a record and give it a spin.