I Possessed a Madman in the Tang Dynasty, With Just One Shop From the Start

[Funny + Lighthearted + System Story] The protagonist, Li Ping'an, was a third-year student at a top-tier university. One day, while taking care of business in his dorm room, everything suddenly went black and he passed out. When he woke up, he was in a little shop with an ancient Chinese style. At first, he thought his roommates were playing a prank on him. They had even hired “actors” outside, and he had to admit it all looked incredibly convincing. But when he went around asking “the actors” about it, they all looked at him as if he were an idiot. Suddenly, memories belonging to this body flooded into his mind. This was the Tang Dynasty, during the reign of Li Shimin, after the Xuanwu Gate Incident. It was also the height of the Tang Dynasty, and this place was Chang'an. The original owner of this body was also called Li Ping'an. He was a fool and a madman known far and wide, and an incredibly handsome one at that. After his parents died, he squandered the vast fortune they had left him, until all that remained was a little shop. After a long while, Li Ping'an finally accepted the fact that he had transmigrated. “I was just jerking off. How did I end up here? Well, at least the Tang Dynasty is flourishing, even if the original owner was a wastrel. But how am I supposed to make money now? Brew liquor? Make soap? Or...?” The original owner had been addicted to gambling and had debts to repay. The creditors would be coming soon, and if he couldn't pay them, he was done for. Just as Li Ping'an was at his wit's end, an electronic voice suddenly sounded in his mind. “The Great Tang Supermarket System has been activated!” “The System?!” Li Ping'an was overjoyed! “A shop registered under the Host's name has been bound. One Newcomer Gift Pack has been issued: the realm of a Grandmaster of Martial Arts.”