Not in 18th century. You could get a gun then for about month's wage of a skilled worker. Not exactly cheap, and significantly more expensive than now, but not exactly impossible to have even for a skilled worker or a middle-class person. And there are now firearms in that price range, though many common ones are significantly cheaper. Something like a cheap car - not pocket change, and you won't get one unless you need one, and if you aren't rich you probably won't get more than one - but for most people, not out of reach entirely.