Part of what makes blue the most loved and hated color throughout Magic: The Gathering history is its ability to counter spells. And among the counterspells, few come close to the power level of Force of Will. Being the first counterspell able to be cast without paying any mana, Force of Will forever changed the landscape of the game.
Counterspells are also known as permission spells because they make players sitting across anyone playing a blue deck ask "if it is okay" every time they cast a spell. In the first couple of years of the game’s existence, permission simply had to be asked if the blue player had left enough mana untapped to be able to cast, for example, Counterspell, Spell Blast, Power Sink, or Force Spike. When the blue player has tapped out, there's no longer a reason to ask for permission, since no mana meant no ability to counter.
This all changed in the Summer of 1996 with the release of Alliances (June 1996), the eighth Magic expansion. Among the set’s 144 cards was a cycle which was to become known as the "pitch cards" due to their alternate casting cost, making them castable without mana by exiling a card – and in some cases, as with Force of Will, paying one life.
Few cards have affected the way Magic is played as much as Force of Will. There is a clear divide between Magic before and after the printing of this card. Players facing a blue deck can no longer skip asking permission when their opponent is all tapped out – at least not when the opponent has a hand of two cards or more and a life total of two or more. With Force of Will, the days of feeling at ease, casting any and every spell as soon as the blue player taps out, had passed.
The best way to avoid having to concern yourself with your spells being countered by Force of Will is not to play Vintage or Legacy at all. Joking aside, according to MTG Top 8, Force of Will is played in 50.0% or more of all Legacy decks and around 60.0% of all Vintage decks, usually with a full playset in the deck. Having too many copies of the card is rarely an issue because an excess Force of Will is the perfect card to pitch when casting Force of Will for free. The card is not tied to any particular deck type, but usage is rather restricted by whether a deck has enough blue cards to have something to pitch when countering. Force of Will is also legal in Commander, where it is usually only deemed interesting in more competitive metas.
Before the full list of cards printed in Modern Horizons (June 2019) was revealed, Force of Will was one of the cards a few players feared, while others hoped that the card would be introduced into the Modern format through this release. In the end, Modern had to make do with an all-new free counterspell, Force of Negation, disappointing some while making others breathe a sigh of relief.
Being the only version of the card printed at Uncommon, the original Force of Will from Alliances is the cheapest tournament legal version at just above 50,00 € for a near mint version. The only regular reprint was in Eternal Masters (June 2016) where the rarity had been upgraded to Mythic. With the card accordingly being available in a substantially smaller quantities, prices from this set begin at around 80,00 €. Additionally, there have been two other special printings as a Judges Rewards Promo in 2014 (available from 265,00 €) and as a part of Amonkhet Invocations (April 2017), which currently begins at 175,00 €.
Since future reprints seem more likely to feature the illustration from the Judges Reward Promo or perhaps even Eternal Masters, the original and the Invocation versions may turn out be the best bet of this card with the biggest potential to increase in price. They're also least likely to take a beating pricewise as a result of an increase in supply. However, being one of the most played cards wherever it is legal, reprints are unlikely to fulfill the full demand and completely collapse the price of any version of Force of Will.