If you change your cell number to the local exchange (913) the calls will become local calls from the prison. Use Western Union and send money into the inmate's phone account and he will then be calling you at the lower rate.
https://www.inmateaid.com/ask-the-inmate/if-i-have-my-cell-changed-to-a-913-will-it-be-long-distance-from-leavenworth-also-is-it-cheaper-for-me-to-add-time-on-my-phone-number-or-for-the-inmate-to-buy-a-phone-card.amp#answer
Accepted Answer Date Created: February 02,2013