Gun shows, gun shops, classified ads, estate sales, online auction sites
One of the main advantages of air rifle hunting is that it's easy to use, gives you cheap practice and is also good for hunting small game. One of the main disadvantages or air rifle hunting is the fluctuation of pressure in relation to ambient air temperature.
Hunting rifle scopes come in a wide variety and are easy to find online. Some websites like The Scope Smith and Optics Best Buy offer hunting rifle scopes.
Sorry- no one answer- you did not say what you are hunting. You can get a decent used .22 rifle for about $100. Rifles for larger game may start at about $200, and go up from there. Depends on what you want to buy- like cars.
You can do a Google image search.
A good place to find cheap rifle ammo is at J&G or The armory. They have sale on this stuff in bulk. You need to be very careful and make sure to clean the camber and let the rifle cool before you use it for the second shot.
You will have to define cheap
What does "cheap" mean to you in terms of money? Try pawn shops, gun shops, gun shows.
H&R Handi-Rifle
it depends on what your hunting
Hunting rifles tend to be lighter, have more slender barrels, and sights that are useful for hunting. I have one target rifle that weighs 12 pounds, and has a 24 power scope. It is an excellent long range rifle when fired from a benchrest. I would not want to carry it any great distance, nor fire it standing offhand. The scope would have such a small field of view, it would be very difficult to FIND a moving animal in it.
One may find cheap hunting gear on sites like eBay and Amazon. One may also check local boot sales and some high street retailers that specialise in outdoor survival.
Define "cheap"