I feel like that the forum did merits to get quality post. And the main reason is to limit the amount of people on that rank. Without those merits people can easily become a Hero member in a few months. But because of merits they have to make quality post rather than making average post and getting the same out come. So I feel like trading merits is not ideal maybe even illegal. Because what's the point of selling merits if you will not earn it again?
You can merit any post which you can like, even if it is a single word reply but if you are doing this for getting something in return which makes you as untrustworthy person but you won't get banned only will get negative trust ratings from DT members.