My favorite cheap one would be a Schrade 34OT.
A good friend managed a Pawn Shop, so I would get to see stuff before it went out for sale. One day he had a 34OT laying on his desk, I asked if it was going out for sale, he said yes.
He was going to put 20 dollars on it, but told me if I wanted it, I could have it for 5 bucks. It had seen a little use, but not much, and had never seen a stone, so I grabbed it.
It was the first knife I was able to put a really good edge on freehand, and still sees pocket time once in awhile