The Spell Card Shop is the only place in the game where players can purchase a three-pack of spell cards at the cost of 10,000.
Greed Island arc
As the senior member Jispa guides the new alliance recruits to the alliance base, he elaborates that the new recruits' job will be collecting spell cards from the Spell Card Shop in Masadora. Furthermore, Jispa details that the alliance has managed to collect all forty spell cards in the game. This allows to trade all the spell cards they've collected for the ultra-rare SS-Rank card "Angel's Breath" at the Spell Card Shop.
Surreptitiously tailing Gon and Killua, an apprehensive Motaricke intends to use the "Thief" spell card to steal Killua's "Sword of Truth" card that he won in Antokiba's monthly tournament. Motaricke acquired the rare spell card in the Spell Card Shop after enduring a strenuous endeavor to get there.
To combat and protect themselves from the issue of being defenseless against spells, Gon and Killua plan to head to the Spell Card Shop in Masadora. To reach their destination they purchase an empty map and ask the Trade Shop NPC in Antokiba for directions to Masadora. They follow the NPC's directions and Biscuit Krueger, their new Nen teacher, joins them. Gon's team finally makes it to Masadora and the moment they find the location of the Spell Card Shop to buy spell cards, they're forced to return to the badlands for more training.
From what Abengane divulged, that Genthru is not only the Bomber but he may intend to kill all of the alliance members with the bombs he's rigged on them. Gon and Biscuit decide to finally go to the Spell Card Shop to buy spell cards. At the shop, they're told that a new shipment has arrived and the two figures that Abengane was right about Genthru's intention. So they both buy up to sixty spell cards, one of which is a super-rare card.
Sequentially culminating a bunch of new Restricted Slot Cards, Gon's team decide to go to the Spell Card Shop again and purchase more spell cards. Meanwhile, Genthru and his partners Sub and Bara have a conversation involving the rival Team Tsezguerra. The Bombers suspect that Tsezguerra's team might be holding a "Voucher" card by trading in 40 spell cards at the Spell Card Shop. This suspension is proven true as Tsezguerra's team has managed to procure a "Voucher" card.
After Team Tsezguerra declares war on the Bombers, Goreinu acts as the team's proxy for buying spell cards in order to keep the Bombers at bay. In retaliation to this, the Bombers ambush players that go to the Spell Card Shop and have anyone that doesn't have Tsezguerra's name in their binder buy more spell cards for them. The ones that do have Tsezguerra's name in their binder are killed by Genthru, and Goreinu reports this to Tsezguerra. Amid the pursuit between the Bombers and Team Tsezguerra, Goreinu reports in the downtime of the pursuit that Sub and Bara have switched out with their fakes to stake out the Spell Card Shop again. Sub and Bara report to Genthru that during their stakeout they only managed to catch one person.
The Bombers wait in front of the Shisho Tree in hopes of ambush Team Tsezguerra when they return to the game. However, Team Tsezguerra never return in time to avoid losing all of their cards due to the stature of limitations on card reserves when outside of the game. So the Bombers head to Masadora to buy more spell cards and Goreinu reports the Bombers movement to Team Gon.