Sorcery contested realm Promo's and prices?

Sorcery contested realm promo card values seem to be all over the place. Most of the promos do not have values listed, even though they are listed in tcgplayer. On the other hand, the sorcerer from Arthurian legends store kit has a value of almost 400usd when it’s market price in tcgplayer is 105 usd. (in tcgplayer, the card is listed as Sorcerer (store alternate promo) foil - arthurian legends promo)