I like this idea. It gives people an opportunity to receive a rank, who previously were not able to purchase a rank. But a little question: Would you be able to save up for a rank such as Foxking? Or is it just the first few ranks?
Why don't you just make it so if people get lets say 50million on a server they can upgrade to donator then 100 for vip and so on price doesn't matter just make it balanced for the server