I really like the idea, most mmorpgs have this. $50 is a bit hefty though, if you were to make friends on the chat, after a conversation, you'd find yourself ~$1000 down. Maybe have the stuff you want to advertise in a special colour? so it stands out more?(but it would cost $50) And have the normal chat in the basic white so it would be free or cheaper.
Also, when are you updating Rufus' hat shop again, i saw a day or two back you said you'd do it but you never did? :<