I Own a Yin-Yang Pawnshop

Twenty years ago, tycoon Zhang Dafu pawned twenty years of his life in exchange for two billion in startup capital. Now the twenty-year term is up. Under the contract, he must pay forty billion in interest, and redeeming those twenty years of life will cost eighty billion...

After becoming the owner of the Yin-Yang Pawnshop, Lin Yang discovers that as long as the values are equivalent, he can trade anything.