I don't know about cheap (as these old Mossberg rifles seem to be growing in popularity again), but you could give Vic or Cheryl Havlin a call for availability and pricing. They run the Mossberg collectors association (the only one recognized by the Mossberg family). They also have a website. Here you go...
Hope this gets you pointed in the right direction!
"Despite our ever-changing, ever-indignant world with its growing ignorance of and indifference to the ways of the wild, I remain a predator, pitying those who revel in artificiality and synthetic success while regarding me and my kind as relics of a time and place no longer valued or understood. I stalk a real world of dark wood and tall grass stirred by a restless wind blowing across sunlit water and beneath star-strewn sky. And on those occasions when I choose to kill,....I do so by choice, quickly, and with the learned efficiency of a skilled hunter." -- M. R. James