Saving 80,000 Gold in Another World for My Retirement 6 (light novel)

Joining forces with the ambitious merchant Lephilia, Mitsuha is on a roll in the New World. But now their inventory's been stolen by a jealous rival! She's not letting them get away, though. It's payback time-with the cunning use of her world-jumping ability, of course. In this volume, our heroine is cooking up even more storms: an exclusive club for young noble girls, a manmade island, and a new kind of weapon that'll knock a boy's socks off?! Sure, saving up gold coins for her retirement ...