Yes, there is a small monthly fee and an interest rate based on approval.
You can pay off your financing through Affirm early with no pre-payment penalty.
Regarding Fixed APR Offer, customers can pay off the full amount earlier without penalty and can make larger payments so they can pay off the loan earlier. To do this, customers just have to call Affirm Client Relations number ((855) 423-3729) (the monthly fee does not apply to Fixed APR) or refer to this website (https://helpcenter.affirm.com/s/article/make-a-payment)