mog555,
I will try not to make you feel bad about the newer Chinese slipjoint knife purchase you made recently.. Rather, I will be positive and tell you what I do about once a month or so. When I decide to purchase a slippy user and want one that is pretty high quality-high quality to use:
I will spend one week watching and bidding on the bay for all the
excellent grade-very good grade vintage traditional slipjoint knives I can find every night(for about 20-30 minutes or so) or nearly every night, and then check back often as I can. I don't have a computer at work to use but fellows that do could really invest much more time into this project.. Anyway at the end of the week, typically I find more than several that are in the hopper that appear to be under-priced at current market value. At the end of the weekend I seem to find one that will be mine at the end of the auction for a bargain.
There is allot of process of elimination due to seller BS and or unanswered questions. However, you will find some good honest sellers that have older fine valuable folders that are less than mint and therefore are not at collectible value, but have fine character that have not been abused and will function as the best users you will ever own. You just have to ask questions and sometimes get additional photo's and it does take an investment of a little time at night while on the internet to do this research..
However, it does pays off.. Here was an old Remington Texas Toothpick from the 1940's or so, perhaps slightly earlier with a very small amount of blade wobble, a little pitting on the used carbon blade that still had about 75-80% of the blade left to use. The blade also had the pitting attempted to have been removed by an armature with what appeared to be a dremel tool..
The upside was that the knuckle-head with the dremel tool figured it out before ruined the blade. And the bolsters seemed nearly in excellent shape and the coffee colored bone scales were without blemish of any kind and all delivered to my door for just under $29. This is not the very best user knife bargain I ever had but damn close and not bad for what is typical if you follow this advice...
Another more recent example I have won is a 1974, 6 dot Case Barlow 6202 1/2 that I picked up about a month ago that I got for $18. and change delivered that has both blades 96%. It had allot of patina and some corrosion but no other issues.. Sorry no pics yet..
All the best with your quest ~ ><> ~