Place any bottle of nail polish in this holder while you paint your nails. It will tip and wobble but never fall or spill. When you want to get more polish on your brush, tilt it to one of the sides and it will hold steady for you.
Plastic -- $1.50 (66g at $22/kg)
Silicon circles -- $0.09 (6 sq in cut from baking mat)
Foam -- $0.07 (cut from sponge)
TOTAL -- $1.66
Commercial equivalent: $13
Savings: $11.34 (87%)