Lots of choices, Spyderco makes my favorites in this price range, but what matters is what you expect it to do.
At $50 and under there are trade-offs, heck even at over $500 there are trade-offs.
BTW, my first folder getting near the $50 mark was a Native, still love them, but if I were doing it again now it would be either the 4th generation Delica or Endura.