Hello guys, I can't seem to find an up-to-date rankup plugin. Basically, a player starts out as a Default rank and in order to go on to the next rank, in this case which is Imp, they must type in something like /rankup, but it will cost them $750 in game money. That's an example. They will need the node for ranking up though.
This plugin, MasterPromote, also fits your request, and there are a lot of possibilities with it! Requires Vault