Buy-a-Box

Buy-a-Box promotional cards are cards given away for purchasing a booster box of Magic cards at certain local game stores.

History
The Buy-a-Box promotion is designed to increase box sales at local game stores. Initially they were foil cards with alternate art, bearing the five mana symbols arranged in a circle as a watermark. From Dominaria through Core Set 2021, they were unique cards that were part of the relevant set, but couldn't be found in booster packs.

In 2020, an additional Buy-Any-Box was introduced. This was given away when any Booster Box was purchased.

List of Buy-a-Box promos
The following table is a list of booster box promo cards: Exclusive card, not found in draft booster packs of the main set.

Controversy
As the promo for Dominaria, Firesong and Sunspeaker, was the only way to obtain this card, its release was heavily criticized. A comparison was made with the exclusive release of Nalathni Dragon in 1994, after which Wizards of the Coast had vouched to make all cards available one way or another for the main public. Because it had served its purpose (promoting local game stores and furthering sales), WotC decided to offer a mechanically unique Buy-a-Box promo card at local game stores with each major set release for the foreseeable future. However, they held the possibility open to reprint the promos in other products.

This controversy only magnified with the release of Core Set 2019 and Nexus of Fate; while Firesong and Sunspeaker was of a medium power level and likely not required for any more than one copy per player as a Commander, Nexus of Fate was radically different. The ability to take another turn is extremely powerful, and the in-built recursion incentivizes players to run a full playset; ultimately, Pro Tour 25th Anniversary had several successful pilots of Turbo-Fog variants with playsets of Nexus of Fate, resulting in a massive spike of the card price. The next two promos for Guilds of Ravnica and Ravnica Allegiance passed without incident, but Nexus of Fate's problems were clearly more of an issue of card power and the promo card status only served to exacerbate controversy over its unfun gameplay patterns. This led to a ban in Arena Standard. Since, R&D intends to be more careful with the Standard viability of the Buy-a-Box cards, but they don't intend to stop making them.

The promo for Throne of Eldraine, Kenrith, The Returned King was a card that saw widespread play (2-4 copies in a top metagame share deck) for six months. However, during that time, very few high-level Standard tournaments were held on paper (as opposed to on MTG Arena) and the ones that would have been were cancelled in the wake of the COVID-19 outbreak, mitigating the discontent regarding obtaining such a card.

A a result of the player feedback, Buy-a-box cards reverted to non-exclusivity with Zendikar Rising. However, reprints that are released exclusively as Buy-a-box promos have continued in supplemental sets such as Commander Legends and Modern Horizons 2.

Box toppers
Another take on booster box promo card are the box toppers. Unlike Buy-a-Box promos, these are packaged within the booster box.