Isekai Ojou-sama

The richest heiress in the world, Touka of the Tsukizakura Conglomerate, dies in a freak accident… and wakes up in another world—Megalanica. Captured by a wicked king and forced into slavery, her fate seems sealed… until she activates her unique Authority: Gravebank, the Bank of the Underworld—with a jaw-dropping balance of ¥70,000,000,000,000,000. Armed with absurd wealth, Touka buys back her freedom—then sets out to free others like her. Now, with gold as her weapon and a growing party at her side, she begins her journey to buy the world itself—and bring down the demon kings who rule it.

(Source: Comisma, translated)