PMR446 (“Personal Mobile Radio”) is a European standard for licence free wireless communications. Radios (usually “Walkie Talkies”) following this standard are usually very affordable and easy to find.
Together with the “Geekcreit UNO” Arduino-clone I also bought a 16×2 LCD display from VNG Systems. The Hitachi HD44780 compatible display has a I2C serial interface module soldered on the back. The information I found