Like most Magic: The Gathering cards, the value of Mind Flayer depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Adventures in the Forgotten Realms)
Misconception #2: Between frequent Masters sets reprints and the fast-moving metagame, you should avoid buying cards from Moderns top tier unless you absolutely need them
Prior to this latest reprint, this card typically sold for $35 at least, since its a true staple in Commander
(You can always play Special Guests cards and cards from The List in any format where they are already legal, such as Pioneer, Modern, or Commander.) Cards from The List are direct reprints featuring existing artwork and treatments (with the addition of a small Planeswalker symbol in the lower-left corner of the card), but Special Guests cards are reimagined in the style and aesthetics of the setechoing Ravnica's guilds and citizens with new borderless artwork
Consider that many current decks in Shards of Alara Block only have a handful of lands that can even come into play untapped, let alone basics
