I felt sad regarding this issue, the purpose of merit is to improved ourselves to give quality post. Selling merit is not helping' you just torelating them not to improved themselves, it is a part of the rule so we need to follow.
Just report those people who are selling their sMerits and they shouldn't be tolerated and when you found one you are contributing to the forum.
how to get merit?
Write posts that has sense and has quality.