What's the commission rate if you are using an outside sales person?
Whatever you negotiate with that agent. If you're selling ice cubes to Eskimos, you might negotiate 40 points. If they are selling cold water in Hades, you might go for 1 or two points.
As for the "going" rate in your location and business endeavor, I haven't a clue. I have always worked it the other way: I tell him what my rates are and I add his take on top. If he sells, I am happy and so is he. If he sells a lot, I'm happier and so is he. This only becomes a problem when greed rears it's ugly head and one party or the other starts thinking they aren't getting their share.
A good sales person is difficult to find. If you find one, don't feel bad he is making a "killing" on you. If your rates are right, you should be smiling too. Furthermore, don't be angry because he is making six figures while you are making 5. If this is the case, move your rates, not his, because a good salesman is hard to find. Truly successful people surround themselves with people that are better than they are.
Just my 2 cents.