When strapped for cash before his next paycheck, Ryo Takezawa would trudge over to the nearest Bookoff, the nation's largest chain of secondhand bookstores, to sell his novels and CDs.

But the buyback rates were meager: The 37-year-old temporary worker was lucky if he was offered ¥100 for a hardback book in near mint condition. A box full of books and albums would get him a few thousand yen at most.

Now when he is falling short of resources, he thumbs his smartphone instead and goes on Mercari. Of the 15 items he recently listed on the popular online flea market — volumes of manga, a shoulder bag, DVDs and electric guitar effectors — 13 found buyers who paid a total of ¥50,000.