I Become Strong by Spending Money at Hogwarts

Waking up, Joel found himself transmigrated into the magical world of Harry Potter, bringing with him a "Pipi Shrimp" pay-to-win system.

Charms, Transfiguration, Potions...

Spend money + grind = boundless magic!

But slowly, Joel discovered that this system was as mischievous as its name suggested.

"I absolutely cannot do something like that!" Joel vehemently refused a system-issued task.

One morning, Professor McGonagall's office doorknob mysteriously vanished.

The Gryffindor lioness was furious, while Joel, tucked in a corner, contentedly watched his Transfiguration progress bar tick up on the system panel.

This is a story about a protagonist making money and causing mischief at Hogwarts.