WhatsApp is undeniably one of the biggest players in mobile messaging, with over 600 million users worldwide and a recently released desktop client to accompany it. Using internet/data on your phone instead of messaging fees, you’re free to message your friends and family anytime, which has made the messaging application so popular for those traveling. Without having to accrue ridiculous roaming fees, WhatSim is a SIM card specifically for those traveling and wanting to use WhatsApp. The single SIM card works with over 400 carriers in around 150 countries, letting you chat on WhatsApp freely for a minimal $10 USD for the card. If you’d like to exchange more than messages, you can purchase credit packages to share pictures, videos and more.