If you are mechanically inclined the you can buy all the parts for an ar-15 and put it together yourself in whatever caliber you want. You may also be able to find an ar-15 in 5.56 nato for that price. I haven't seen them in larger calibers for that price though. It is America's rifle and the most accurate for the price. That does not mean it's the best option.
Used Ruger Mini-14/30's can be found for that price but stay away from the old ones, they have horrible accuracy, the newer mini's with thicker barrels are much better. You can't complain when you get three inch moa when mini-14's have a 5.56 nato/wylde/or their own concoction of a chamber that shoots 5.56 well (1.5 moa) and .223 ( wolf, pmc, herter's, or any other cheapo crap ammo) not so well with 3 moa or worse and then complain about horrible acuracy. Yes PMC is crap ammo.
I know that I will get flamed for suggesting the WASR-10 but I don't care. Look it over for bent front sight (the pin not the sight block). Use only new magazines. From my experience the problem that most people have is jaming issues. This is because they watched a youtube video that shows some moron or hillbilly with a WASR that has never been cleaned and they are using surplus mags with worn out springs (soldiers load magazines and leave them that way for a long time, loading mags while the enemy is shooting at you kind of sucks). Mine came with tapco mags and they have been flawless. My friend has the same WASR and was trying to use surplus mags (they were cheaper by $1 than the tapco mags) and had feeding and jaming issues. He got his tapco mags out and the problems vanished, go figure.
Best of all the WASR is easy to field strip and clean (wondering why these hillbillys can't clean them, but I know why they use the surplus mags) than either the ar-15 (hardest to clean but still easy to field strip) or the mini-14 (quicker than the ar, harder to strip than the WASR because you need something to put in the hole in the trigger guard to pop it off). All in all get what you are comfortable with and I hope this has been helpful. Yes I have a copy of each, I like them all. Let the flaming begin!