Motor Carrier Fair dispatch fee


My husband and I have our own trucking business, and I have been doing his dispatch for the last few years. A little over a year ago, I helped a neighbor (who had his own truck) find his loads, did his paperwork, etc. - basically became his dispatcher. I did this for a few months until his wife took over. Now I have been asked if I would be willing to do the same for another owner/operator. Since he runs the same type of equipment as we do, it's not a huge hassle, other than the paperwork. I was charging the other person a flat fee per load, which he was fine with, but I also felt some days like it wasn't quite enough. Just curious for those of you that hire outside dispatchers, what is a fair fee to ask per load? I want to be fair, but also don't want to get burned out if I'm not making enough for the time I invest.