Today I was driving up Sheridan Road through Zion, Illinois. There were at least 3 trucks selling either watermelons, squash, greens and crowder peas.
I bought a bushel of crowder peas which took 4 people roughly 3.5 hours to shuck (we did eat dinner somewhere in there).
The crowder peas cost $20 a bushel. Earlier in the season the guy sold string beans for $15. a bushel, I paid $24 from another vendor. He also sells sweet peas in the spring. I have his card, next year I will follow up and advise.
You can buy in more modest quantities ... I tend to go a bit overboard.