Become a Profiteer to Pay Off Debts

During the time travel, I accidentally smashed into someone else's store, so I started working as a wage earner in order to pay off my debts. But there are almost no customers in this store. How long will it take to pay back the money? I can only think of other ways. How about I become a businessman, but serious businessmen don't seem to make much money. They still have to buy something that people can't refuse. To become a profiteer, it's best to sell something that no one else has. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.