In Marlboro, before I transfer, 1star hq items can be sold for a profit of at least 10k, usually at 15k... That's your way above equilibrium example. In Tonbery, you sell for a profit of 2-3k...both operates with the same market mechanism. So market size plays a huge role here.

The question remains weather the inefficiency caused to the market by restrictions and barriers is worth it or not. In my opinion, no. Artificial control/manipulation of the market is almost always a bad idea in a simple market such as a game market.