My neighbor and I paid $600 to rent a bull for 60 days a few years ago. Delivered and picked up.

If you want to avoid cash exchange then I would think that this is about one very good current spring heifer calf exchanged at the completion of breeding in August. Possibly two. Late enough so could be weaned.

I've always seen bulls rented on a time basis rather than a per head basis.  Otherwise if a guy just has a few cows it is not worth the bull owner's trouble.    

Thing that always concerned me about renting a bull is what diseases is he bringing or leaving with???  Good luck.

Jim at Dawn