Hit up your local pawnshops. You'd be amazed at what you can pick up.
CVA Hawkens seem fairly common. They were a fairly cheap gun new & it would appear that a lot of folks bought them & either never used them, or shot them a few times & gave up. They're not a brilliant gun, compared to some, but they're as accurate as anything else & you're in with a really good chance of finding a nearly new rifle for well under $200
I've personally bought 4 of 'em this year (To sell on) & never paid $150 yet!
Gunbroker is usually pretty handy too. Keep your eye out for Traditions, CVA, Gamester, Jukar & Thompson Centre rifles. The TCs tend to fetch a bit more than the others, but are much better quality (genrally speaking) If you are buying used, invest in a borelight, or one of those little bobber lights Walmart sells for fishing. As long as the bore is good, everything else can be repaired, replaced, or lived with. You can buy the most expensive, beuatifully handcrafted rifle ever made, but if the barrel's junk, it's nothing but a fancy ornament. You want to be looking for good, strong rifling with few or no pits. It pays to take a range rod with you when you go to look at a gun too. Run a dry patch down the bore, on the correct size jag & it'll let you know if there's any snags, swells, tight or rough spots or rust down there (It'll also let you know if it's been left loaded too. 2 out of those 4 I mentioned, still had maxi bullets & powder in the breech!)