But if they do that then the prices will skyrocket up. Then no one would buy them. A way that they could do it is if You buy a rank, for example, MVP+. This is $20 a month, after a year of continuously buying they get VIP+ for the rest of their time on the server. If someone buys VIP for a whole year they could get something like half of their perms for free.
Another way they could do it is after a period of time, the rank becomes up to 70% off the original price.
Or they could add permanent ranks along the monthly ranks.