No, sorry but that won't stop account farmers. I don't know how you and digaran end up with an idea like that but the fee? It will be useless.
How easy it is to pay that one time fee and get it back with profit right after establishing your account for signature campaigns?
Lol. straight to the point. just no, sorry.
None of the account farmers could afford to pay $200 and if they could afford it, forum would have money to hire more moderators. it would certainly be harder than posting garbage for free and have your post count increased. there are many people who'd post with Jr member accounts. they don't care about ranking up.
Do something worth receiving merit, you will understand the feeling.
You could keep posting for free any where you'd like, you could even receive merits but never to rank up without paying first. how many forum member accounts have no signatures? maybe 5% of members have no signatures, this means the rest are earning money by posting here, even now street beggars could register and start posting to earn money here.