Time to do your research, few stopped merit source (by total merit sent & received/sent merit ratio)¹ participate in paid signature campaign. Besides, AFAIK theymos never said that as requirement to be a merit source.
Additionally, selling merit is the fastest way to lose extra income.

Source :
1. https://bitcointalk.org/index.php?topic=4523027.msg40734583#msg40734583


Thanks