I haven't bought an under $100 knife in awhile, but I've heard good things about the Spyderco copies, Bird I think is the name of the brand. CRKT is the last "cheap" knife I bought, they seemed to work well enough.
They don't come up for sale too often on here, but if you could spare an extra $40, that Zero tolerance 0350 that just sold on here was a great knife for $90.