After giving it some thought, I think there are four categories of overpriced cards:
1. Cr speculation: I remember Dahlia being over 22k, and Hawkins
14k right before the last Cr announcement. Currently, Jungo
are going through a similiar phase.
2. Noob favorites: Some cards look very, very strong at first glance, and since there are a lot more noobs than pros in this game, they tend to drive up the demand (and therefore, price). Hammer
and Amber seem to fall under this category. And yes, I know there are legitimate uses for Amber but 80% of the time I see noobs with Amber, Kolos
and two 2*s trying to 1hko.
3. pfull potential: 4*s and 5*s are always worth at least 3~400 clintz unleveled, and 5~600 clintz pfull, even Candy Jack
. I guess you can call that "overpriced" in terms of thier limited ability to win games, but that's not why you buy them.
4. Rarity: Vholt
would be worth 120 clintz if you got him at level 5 instead of 50.