I find receiver tube hard to find locally, the last 4ft section I bought was from Etrailer. shipping was free because I had over 99 dollars on the order. Shipping a 4ft section would probably be expensive on its own.
I went to the local metal shop and picked up 4ft of receiver tubing for $25 and two 4ft sections of 3” wall C channel for $26. The store is called Discount steel off of hwy 156 in north Saginaw TX . Any recommendations between a lock-n-roll vs max coupler?