Lol, wow, and are these massive spiders who fire acid out of their fangs at theifs?
I think another option would be a \"Town NPC\" with telepatic communication skills, who could relay messages to someone else and they could have it appear on their screen. It would be limited but much cheaper than buying a rock, maybe even have it so if yourve both at an npc that has this ability you can chat with you being charged over the time you use.
Just ideas anyway...