Some years ago, I made this machine handgun rest using two industrial ball bearing pillow blocks on a fabricated steel base. It includes both windage and elevation adjustments, and uses two adjustable Chevrolet valve springs and leather washers to control the absorption of the recoil. I estimate that I have about $125 invested in it. It is quite heavy (30 lbs. or so) and easily clamps to any sturdy shooting table. I made a set of dies to stamp out the leather washers, although the ones in the unit have lasted for years.
Regular Ransom Rest grips can be used, or your own grips can be easily milled out of 3/4" plywood to save money.