Some lenders provide lock-ins without cost, others have a charge.
The longer the lock-in, the greater the risk to the lender, and so the more likely a fee. The best lock-ins place a ceiling on both rates and points. A lock-in that only caps rates and says nothing about points exposes a borrower to very high fees should rates go up. This means that if rates fall prior to closing, the borrower can re-lock at the lower rate. Speak with lenders for specific programs and options.