Yes, Penmate is free to download...

Penmate

Name: Penmate
Rating: 4.54 (169 reviews)

4.54

Downloads 50K+

Developer Penmate

Category Social

Android OS Varies with device

Penmate is the easiest way to write incarcerated loved ones in jail or prison. Just search for someone and send a message in minutes. You can upload photos from your phone and deliver messages, photos, and postcards to any jail or prison. No stamps needed. Try it out!