Try Buck. Their Hunter(110) and Ranger are both available for under U.S.$50. You might be able to get an XLTi for 50-60, which is the best of the bunch. There's a reason it's the folder I carry.
Honestly, I wouldn't want an expensive folder. Just too likely to get lost or confiscated, or even stolen.
Anyway, nobody makes a folder yet that, after all is said and done, could get me to trade my tried and true Buck. It's a good combination of blade, handle, and lock. There are knives that equal or surpass it it any one, or even two, areas, but not all three. Not by my standards anyway.