From myfico:

What to know about "rate shopping."
Looking for a mortgage, auto or student loan may cause multiple lenders to request your credit report, even though you are only looking for one loan. To compensate for this, the score ignores mortgage, auto, and student loan inquiries made in the 30 days prior to scoring. So, if you find a loan within 30 days, the inquiries won't affect your score while you're rate shopping. In addition, the score looks on your credit report for mortgage, auto, and student loan inquiries older than 30 days. If it finds some, it counts those inquiries that fall in a typical shopping period as just one inquiry when determining your score. For FICO scores calculated from older versions of the scoring formula, this shopping period is any 14 day span. For FICO scores calculated from the newest versions of the scoring formula, this shopping period is any 45 day span. Each lender chooses which version of the FICO scoring formula it wants the credit reporting agency to use to calculate your FICO score.

"Remember, everytime you or you let someone run your credit report your score will drop."

That isn't true. You're allowed to shop for loans, so when your credit report is pulled multiple times within a certain time frame (I believe its 30 days) for the same reason, they are all considered one for affecting your score.

The low interest rates of course are for those that have very good credit. Your credit score affects your credit interest rate. If you don't know your credit score you or your mortgage broker should order a report from all three credit bureaus, not just one. This way, you can get your high score, middle score and your low score.

When you get your full credit report make copies of it and walk around with it so you can give a copy to the mortgage broker(s) that you will visit to see who can give you a great deal. Remember, everytime you or you let someone run your credit report your score will drop.