Establish a bulletin board in each town listing all items for sale, wtb, etc..
Q: Hey, that\'s not realistic, how does this information magically flow between towns?
A: The NPC in charge of the bulletin board will give fed-ex quests to newbies. They\'ll carry little envelopes to the next town, the bulletin board gets updated, and the newbies get a few bucks without having to kill rats.
Practical, \"realistic\", and adds a another tiny facet to the economy.