I typically charge $100/hr.  In order to share the risk, I will defer $15/hr until you win.  If you don't win you don't have to pay me the additional fee.  For example, if I spend 16 hours on your Phase I, then I will bill you $1280.  If you win you owe me an additional $320 Typically, a Phase I proposal takes 10-20 hours to write. 

i will also simply review your proposal and act as a "Red Team".  This is a much more limited effort and I will do this for $500

Marketing and management support support varies, and will be negotiated.

For all tasks I like to use Not to Exceed agreements.  That way we agree in advance on the level of support I provide.