Bid off commisions?

[dknupp]

For those of you that have experience either hosting a bid off or putting calves in a bid off...either spring or fall.  What is the going rate for the bredder hosting the bid off to charge for commision?  Keeping in mind that the hosting breeder does all the marketing, takes the risk of collecting the money, and takes care of the pairs through the spring/summer and incurs breeding cost on the cow.  Any help, thoughts, comments would be great!  Thanks!