If you are resposible for motivating your staff including finacial compensation beware of recent research regarding motivation and commissions
See that attached wordpress file
http://contactignition.wordpress.com/2010/12/16/sales-commission-is-counter-intuitive-call-for-researchers/
And the youtube vlog http://www.youtube.com/watch?v=JeURhaftu5Q
It is essential the employee is paid above average wage plus commission,the latter should be the cream and is an essential motivator in Sales.