Sponsorship and Commercial rates

 currently working with a start up that provides a platform for SME's with business tools to help them get start and grow their business.

I am looking to build the Partnership side of the business bringing in various partners SME's can use. 

when exploring this option does anyone have information on sponsorship/commercial pricing that allows a partner to be a sponsor on the platform. what would you ideally charge them? and what structure would you use? 

thanks