Everyone has some surplus resources of one type and need some other .There are only buy order on market after first few days with people having thousands of surplus resources which other need and vice versa.So People should create a habit of selling extra resources at high price it will force other guys to sell their resources in order to earn money to buy them.It will improve economic activities and make trade embargo useful.Maybe CON can help by decreasing the money generated by provinces so that people are more likely to sell resources.

People will have less money and so they will have to place sell order to earn money so that they buy resource of their choice.This is the main point.