WhatsApp is a very reliable push messaging app, which is not free. What differentiates WhatsApp from legacy instant messaging (like MSN/WLM, Yahoo! or Gtalk) is its 'always on' push connectivity feature. Since WhatsApp is a paid app, some people can't or don't want to pay for it. Fear not! Here are some free alternatives for Android users. 1. Beep (part of IM+) by SHAPE Services. 2. eBuddy XMS by eBuddy. 3. ChatOn by Samsung. There are a few more options out there, but I mentioned these because I've personally used them. I can strongly recommend IM+ and buying IM+ Pro . Since it offers the most value and turns on push for legacy IM services as well. The tricky part will be convincing your friends to use any of the free alternatives.