Typically, Loan Officers will have to pay between $10 and $20 dollars per credit report.  So, for a single-person 3 Score credit report, the broker will have to pay around $10-$12 and around $20 for a joint or married couple credit pull. The broker may or may not mark it up to the Loan Officer, since the more volume a brokerage or bank does, the cheaper the credit pulls. 

If you are being charged $50 for a credit pull, you are paying a 100-200% markup. Personally, I think it's bad form to overcharge on things like credit. Why raise a red flag with a borrower over $30?

Many people assume that they can bring in their own credit and it will suffice. While it gives the loan officer a guideline to work with, they will have to pull your credit at some point. If you are going through a Broker and not a Bank, your credit will most likely have to be pulled twice, as the wholesale lender that the broker is using will pull their own credit report, as well.

For more on how and what determines your credit score check out these FAQ's:

 Paying the Minimum on Credit Cards and its Affect on your Credit

 Minimum FHA FICO score 

 Multiple Credit Pulls and its Affect on your FICO score