Last summer I bought 2 John Deere 640 rakes for $700 on consignment at a dealership.
Both are like me: old, ugly, rusty, and missing a few teeth, but still able to get the job done.
One came with a dolly wheel and the other did not.
The previous owner told me that he pulled them in tandem with the dolly wheel rake in the lead. Both are ground driven.
The rakes are 4 bar with 5 bar capability. They can be set up for either 2 or 3 rake teeth per section.
Monday night at Tractor Supply I priced new rake teeth at $1.53 each.
I will be raking Costal Bermuda and Cheyenne Bermuda.
Hope this helps. Good Luck!