You cannot go wrong with a Benchmade, although it may be a little higher than your budget, you'll get over it quickly once you get used to having a knife with you that never makes you wish you'd bought something nicer in the first place.
If you use your folder for camping purposes I suggest you try a broader blade folder and a lockback.
My choice would be the Boker M type or the Boker Trance. Both are frame lock knives which are a little more studier that the linerlocks, IMO, and has broader blades. The lockback knives has the toughest lock, great for camping abuse, you won't go wrong with the Buck line of folding knives.
I agree with this. That 3 oz won't matter when carrying. Thats an extra 3 oz of ROBUSTNESS. And the axis lock makes the knife as strong as any fixed blade. If you drop the price requirements and throw the weight requirements into the air, this is a knife I'd RELY on. http://www.newgraham.com/detail.aspx?ID=5134