A lot will depend upon how large of a raised planting area you want.
Bedders are what some vegetable growers use.
If you use a lister or a middle buster you could throw up ridges to plant on if you used two bringing the dirt together you could then plant on the raised portion. There are a lot of brands of bedders available and for various sized tractors. The disk ones seem to be about $400 and then upwards from there.
Lots of options for making your own. A middle buster with wings added is one I've seen.