That all depends for a part where in the world you are situated. I can't remember when I have seen Instax film at offer on the shelves over here. Furthermore the camera isn't vintage at all.
Over here you can get old cameras that used the Polaroid SX-70 or the 600 type of films for a few dollars. And a European company (Impossible) makes films that can be used in these ranges of cameras which is available off the shelves of the better photo-stores.
Furthemore there is a range of Polaroid bellows cameras that take films still made by Fuji.
Maybe another member has got the time make a list of these three ranges of cameras and the appropriate films.