Replying to Fisheye for film camera

I've been shooting some skiing and other shenanigans on film recently, and thought that a fisheye would be a cool lens for some uses. Anybody have any recommendations for a relatively cheap one (it's something that I think would be fun to mess around with, so I don't want to spend 500 for the canon one)? I currently use a Pentax spotmatic (m42 mount) but the meter is dead and my favorite 28mm lens recently died, so I'm open to switching systems (Olympus om1? Or another Pentax? Idk)

Save the hate, this would be nothing more than something to fuck around with. Since I'm looking to go pretty cheap, should I consider a fisheye attachment for a normal lens?