I have a Ruike P-108 that I like quite a bit. Good action, good feel, a bit showy with out being flashy. Really like the 14c28n steel. Don't really care how long it lasts, for $30 it's a good carry piece.
$40 got me a CRKT Fossil, another surprisingly good knife for the money. Smooth, fast action, solid lock-up, sharp and easy enough to keep that way.
If we take our arbitrary $100 as an upper limit, I just got a Kershaw Launch 8 that I'm really liking. I know it's not a real using knife, except as back-up to a .45, in my case. It's still a really interesting take on the traditional Italian stiletto. And it has, without a doubt, the finest point I've ever seen on a production knife.