Do you have prior military service? Did you take a break in state service to serve in the military?
If you either have military service prior to your employment with the State of Minnesota, or you had taken a pause in your state employment, recent legislation allows you to purchase MSRS pension credits for the time spent in service.
The formula of how much the credit purchase will cost is a function of your individual circumstances. Generally speaking, the closer you are to your full retirement the more expensive the purchase will be; conversely, the younger you are, the less it will cost. Therefore, if you want to make an investment that will pay back over the entirety of your pension, sooner is better!
MSRS will help you determine what your exact cost and benefit are. Check out their portal here.