You know, I don't think new players need to mess with the trade tables right away. They need to earn money and stuff first, then worry about the trade tables later.
Here's my idea: we have it so players with less than 25 hours cannot access any trade tables. This'll reduce the amount of people asking for donations on the tables, and will also help people actually do something in the game like kill players and earn money, other than sit there ask for free items.
The only downside is that they're will be more people at start who "gain hours" by just sitting there. Oh well, all in all, this is do-able and may improve the economy.