What make flail is it? I just bought one that dates somewhere between 1964-1972 it is a Ford, it had been sitting unused and the grease in a couple of the bearings had dried up so I had to purge the old grease out and put new grease in
I used it some and a couple of repairs are needed, I need one bearing on the roller, a new belt and one blade needs replaced, I priced the parts and they come to $167.50
If the flail has been being used some I believe that is better than just sitting, check out the bearings and the belt, if it has new blades you have saved money right there, it is worth the money for sure!
I will have about $400 in mine, along with my time and labor! Have you checked out the prices on a new unit? They can be very costly, a good used mower is money ahead!!