RFP is
Request
For
Proposal
Its basically how an enterprise would send out a lengthy request for a software solution where the response is usually 50-1,000 pages of integration info, source code snippets, detailed info about existing implementations, diagrams, compliance statements, ongoing engineering support, etc...
The deal sizes range from $250,000 to $10,000,000 as a general rule.
As a consultant who helps an organization write an RFP you can charge from $150 to $300 per hour depending on your level of experience on the subject matter. Due diligence for purchases of this size are a bitch.
As a consultant - if you help an organization respond to an RFP from another company you generally make less up front, but get hefty sales guy like bonuses if they win the business. You never run with the sales guys, just help them respond to the RFP or write most of the response sections for them. For example, if I help a client win a $10,000,000 deal, I can expect so much $$ per hour for the time spent plus 1-3% bonus based on the gross profit (likely somewhere in the 180,000$ to 200,000$ range on a 10,000,000$ deal)
You will spend some of your 9 cat lives grinding hard like this.