Resale value seems almost impossible to predict. Some things that were going for way over the original sales prices (like the original grab bag youngs) are now selling closer to their original store price due to newer grab bags being fancier. The second-hand price for even the fancy youngs is lower than some of those first batches were.
Old greens emps were selling regularly for $800-$1000 for a while, but those prices also seem to be coming down.
I guess my point is – things fluctuate so much and what’s popular varies from day to day so if you aren’t planning to sell and want to insure your collection or something, assume a higher replacement cost just in case.
If you are planning to sell and want a good price, watch the classifieds for people seeking the piece actively and how ebay rates are going and try to jump in when things are “up” (like before Christmas/after tax returns) rather than slower times.
This is just a general observation. Trying to decide if I overpaid for something often makes me crazy! LOL