The Federal Government pays the interest on Subsidized Stafford Loans while you are attending school at least half-time (six credits at the University of North Dakota), and during the 6 month grace period. You are always responsible for the interest on UNsubsidized Stafford Loans, but have the option of paying the interest as it is billed or adding the interest to the principal. The interest rate on Stafford loans changes each year on July 1. Check here for the latest rate.
Most commercial loans change their interest rate each calendar quarter, based on changes in the Prime Rate or the 91-Day Treasury Bill Rate. Check with your lender for the latest rates.