Personally, I've always just been motivated by competition itself--I want to be the best. I remember, I did sales for AllState Motor Club for 2 years. The goal was 1 sale per hour. The highest award was for 4 sales per hour, for four hours straight. You won a tee shirt if you did that!! lol. I didn't care about the tee shirt, but I did it several times and was their number one sales person for 2 years straight.
What's my point you ask??? The point is you want people like that, people who LOVE to sell and LOVE to compete, then you don't need to offer them anything other than recognition. If you're a wise broker and have hired the right types (or at least 2 or 3) all you have to do is put a "top 10" or "top 3" or "top whatever" list on the wall and the true salesmen will go bananas!! No fooling, this is true, try it.
Recognition goes a long way. Now some may disagree and say we will only disparage the less successful salespeople, but frankly if they don't like this type of thing I personally think they are in the wrong business. Besides, there is no punishment for "last" etc., as I said, if you have 10 sales people, have a top 3 list. If you have 100, have a top 10 list, and so on. A reward for whoever is #1 at the close of the year would be nice. An incentive might bring out the competitors in some of your less aggressive agents too. Perhaps a trip to Mexico. If one of your people makes you 100k, shouldn't you send them to Mexico??? or something!
Good luck, but again, the REAL key is to hire the right types of people and then mold them I think.