If you pay late, for instance, you will only pay the extra interest accrued on the loan during the period you are late. (valuepenguin.com)
For some subsidized direct loans, government will help the students to pay the interest accrued on their loans during deferment or forbearance period. (myfinancekits.com)
For the last option, interest does accrue on the loan balance which ultimately increases the total cost of borrowing. (studentloans.net)