Newbie Investor - Pre-Approval Question

[Angela Sobol]

Hi BP!  

Looking to potentially by from seller on a condo.  We want to come with our offer and pre-approval letter.  A few questions - 

1.  Where is the best place to get pre-approved?

2.  Should my pre-approval be for the exact cost I am putting down for an offer or can it be a range (pending negotiations)?

3.  Do I have to use the same lender for the mortgage as my pre-approval?  I want to shop around for a best price.

Thanks!