Discerning the difference between temporary spikes and long-term trends is often hard.
Yes, if you are really keen to add an SSK to your collection, you can do it fast, or you can do it cheap. Start tracking prices and dates to determine what the true market price is. That is why I was able to recently post a list of SSK prices and dates, and another list of industrial prices and dates; I had been tracking those sales to discern market price and trends. So when I saw a black M13 for less than $50, and a SSK under $100, I was able to determine that was somewhat below the market price.
Two phenomenon I've noticed:
1) Sellers are sitting on the sideline, and when one sells for a high price, they dump theirs into the market and the price goes down.
2) In the flip side to #1, when one item goes for a very low price, lots of buyers say to themselves, "Wow, I wish I had bid on that." and they set their bid-snipers to maximum, driving the price up.
A marketing graduate student could do an interesting paper on this phenomenon. Of course, he/she would be failed, because graduate papers are not supposed to be interesting.