Extradimensional Crisis will certainly shake up the meta and change how players build their decks, and this is just one example.
That is less of an issue if you have some power enter the battlefield effects, or have spare energy lying around you can easily pay for the mana cost for a turn or two.
Now, depending on what you would consider a "fair" price, your method of determining it may vary, but here's a method I use when looking for a value I can use for buying or trading: select the card and printing (edition) of the card you want to gauge through the search function set the condition, language and other applicable values through the filters if you're a registered member, you'll also get the option to only show sellers from your country
The audience is entirely composed of collectors, making the demographic match as high as any venue in this guide
The set includes unique foils, alternate art, and even some cards with quirky, unconventional designs
Trade-In is not used because theres a chance you could draw Rank-Up-Magic The Seventh One outside your Draw Phase