There’s a few guys who collect them and experiment with them. I’m not aware of anyone actively using them in the lvl9 community (the level 9 large charms with 15 life / AR or mana are the meta)
I’ve sold a few of these maybe 2 ladders ago for 75-100fg a piece. Id assume they are a bit cheaper now since more stuff is out there now.
50-100fg seems fair
Hope this helps 😎