Years ago I needed a cultivator/chisel plow to rip up some ground after construction. I noted a farm auction close to my town that listed a 12 foot pull type chisel plow. Went to the auction and purchased it for $40 (it was in the 80's).
One of the other bidders came up to me, thinking I might be scrapping it and offered me $20 for the two outside extensions--he had a 10ft and wanted a 12. Sold them and he took them off.
Came back with my cutting torch and took it apart. Scrapped the wheels/axles and lift mechanism. Sold the leftover steel.
Was able to build a 6 ft 3PH chisel plow out of what was left.
If you go that route, you can put sweeps or points on it. Or try to buy a cultivator to cut down. It's a cheap way to get functional parts.
ron