There is a sub-genre of isekai (異世界, other world) which involves arbitrage between the world of today and the historical/fantasy other world.

• (Charles Stross, The Merchant Princes) A clan of secretive world-walkers have been using their abilities to build an empire spanning two worlds. An American gets unexpectedly drawn into intra-clan conflict, the U.S. government's covetousness, and the irrationality in assuming there is a highest natural number.

• (FUNA, #Saving80000Gold for My Retirement) After receiving a blessing which saved her life, diminutive teenage orphan Mitsuha decides to amass a fortune sufficient to retire to either world. Luxury-obsessed nobles, plucky young villagers, and a company of flexible-minded modern mercenaries help her establish a foothold.

• (Makishima Suzuki, Welcome to Japan, Ms. Elf!) Since childhood Kazuhiro would dream of a fantasy world. When he and and elf are killed while exploring, he learns that his dreams are real and falling asleep or dying allows him and the person he is touching to move back and forth. Cultural and economic exchange transpires.

• (Ren Eguchi, #CampfireCookingInAnotherWorld with My Absurd Skill) The absurd skill is Amazon (actually Online Supermarket).

• (Hiiro Shimotsuki, Peddler in Another World: I Can Go Back to My World Whenever I Want!) Pretty on the nose.

• (Hirukuma, #RebornAsAVendingMachine, I Now Wander the Dungeon) A sapient vending machine accepts coins in a magical world to restock with items and upgrades from our modern world and the main character's love of Japanese vending machine culture.

#Isekai #LitRPG #LightNovel #Arbitrage #Economics #SciFi #Fantasy #CharlesStross #TheMerchantPrinces #FUNA #WelcomeToJapanMsElf