I was going to post this in the beginners section, but it seems to be the mid ranking members that do this. It is against the forum rules to beg for merit, and not all members are as lenient as I am. If I receive these begging PMs then I just put the member on ignore, so he won't get any merit from me, no matter how good his posting may be. I don't get very many, but I have had a couple recently, so I thought it was time to remind members about merit begging. I don't sell merit either, but it must be over a year since I have had a request to sell merit.
If you want me to award you with merit, apart from the standard awards, then persuade me to revive one of my old projects, so that members can earn merit ,and be of benefit to the forum.
I think it would be better if you expose few of them who PM you for a merit. If you publicly announce who are PM you for merits, they won't get the merit from anyone and it will be a good lesson for them.
Also it will prevent people from further asking for merits in the inbox and this trend will soon end. There could be a thread where everyone could report who is privately asking for merits.