Something I've done in the past is to lubricate the spindle of the fan.
Take it out and carefully remove the foil label on the end of the spindle. With a matchstick dipped in very light oil, drip some onto the spindle and gently spin it, the oil should slowly be absorbed.
You can use 2in1 or, my preference, WD40.
There is no guarantee here and you should be very careful that any excess is cleaned off before replacing the foil label.
Its worth a try and may save the expense of a new fan at least for a while.