I've had a similar problem on one or two knives, although not on my one Old Timer folder, the large Trapper.
To deal with the problem of a blade that's loose at the pivot, on a knife with a press-fit pivot pin as opposed to a rivet, I lightly tap the bolsters together. This should tighten up the fit. Take a hammer and lightly tap on the bolsters around the pivot pin and see what happens. I've done this on a few knives and it worked for me fairly well. Just don't tap the bolsters with too much force, because then there's the danger of tightening things up too much, in which case the blade will be hard to open and close. If the blade ends up too tight, open and close the blade repeatedly to loosen it up. There's no guarantee that this will work for you, but it might, and that's all I can think of. And like you said, it's only a $20 knife. By the way, is that $20 US or Canadian. I've been thinking of buying the mid-size OT stockman and $20 Canadian sounds pretty good. At Walmart it's CAN$27.
Also, try posting your problem on the general Blade Discussion Forum. You'll probably get more answers there.