There are difference in different servers and different levels.
My L17 & L25 teams are in the same server. For L17 team, it is easy to buy and difficult to sell. There are many players on auction. Almost all my successful bids are 1 token. For L25 team, it is opposite. I keep spending only 2 tokens for all success bids. But I lose many auctions.
I think some factors like no. of managers, their financial situation, etc affects the market.
BTW, I attempt to sell a GK of my L17 team for about 10 days. I suddenly remember that I face similar situation many many season ago. At that time, I gave up selling that GK. Instead, I sold the new GK. I don't want to do so in this season because my GK's contract will expire at season end.