That would be nice but I think way above the $100 range if you are looking for cheap.
I did a little test this morning with my pellet gun shooting Crossman flat nosed pellets at a sheet of 1/2" thick plywood. With the Vaseline in the pellet base, it bulged the back side of the plywood, without the Vaseline, there was no apparent damage in the back. So it does make the pellet gun shoot harder. The shots were from about 4 feet distance.
It's right at $200