How much would you pay for a magic sword that leached the life force from your enemies? Or an eldritch staff that let you unleash tempests of lightning? Or enchanted slippers that made you invisible to all but the sharpest senses?

Blizzard Entertainment, perhaps the world’s most successful and prestigious video game developer, will soon test your appetite (and your budget).

The company announced on Monday that players of its coming online fantasy game Diablo III would be allowed to trade in-game loot with one another for real money. The game may be virtual, but the bucks will be actual. With Diablo III, the already blurry lines between virtual and real video game economies will disappear — a potential shift in how players and companies think about interactive entertainment.