It is pretty clear that money alone is not sufficient to motivate a programmer. Things like giving them meaningful, challenging work and providing a supporting environment can motivate them far better than raw dollars.
But for sales, I think it is a different stories. Sales are trained to think in terms of money, and their income is largely derived from commission instead of fix salary. We all think that sales are motivated by money and money alone. But we also know how corrosive money is if it was handled improperly.
How can you motivate a sales person without all the negative consequence?
Hm, first of all is a fact that every person has it's own motivation factors. For someone that is money (maybe for the most people) but I think that is a situation until they get satisfied with their earnings and than they have some other motivation factors.
If you didn't looked earlier take a look at Abraham Maslow's hierarchy of needs - because I think most of people function this way (at least I am).
On the other hand it might be useful to try to find what motivates your sales persons and maybe add some kind of games - sales person of the month, if reach XX sales per day you get a free pizza or some other stimulating "gifts". If it is only money - you can have something like fixed salary + variable part which depends on sales per months (if he/she works more that month he/she will get more money).
Hope I gave some ideas that might be helpful :)