I read this some time in the 80's, and I am fairly certain it was in a magazine (most likely Dragon Magazine).
The story was about a girl who played a thief-like character in an online video game. I think she signed into the game from public booths, rather from at home, and it cost money to play the game.
However, treasure found in the game was transferred directly to your bank account.
The girl's character managed to find a strange magic item (I believe it listed an effect of "unknown", which caused her to suspect she was on to something important). Unfortunately she was then incapacitated by another player, who shot her with a poison dart, causing her to have to manually type to move her feet (alternating commands to move her left and right foot individually), before finally having her character lose consciousness.
There was some interaction between her and the other character (a guy who was implied to be more powerful/experienced/richer than her), and she wound up losing (giving?) the unknown item to him.
At the end of the story, she logged in to the game and found that this other player had figured out how to use the item (I think it let him teleport to hidden areas), and had amassed a huge fortune by using it. In gratitude, he had given her a share of his profits, making her rich beyond expectation.
I'd love to know the name, and more importantly, the author of this story, but I lost all my old magazines years ago.