Ok, well not quite free texts, but the next best thing!
Basically you both have to have an iPhone, get the application called Whatsapp from the app store. The app works like a mix of instant messaging and text messaging. It sends the messages via your internet connection, but it has push notifications and appears like a text message. I use it a shit ton as my girlfriend also has an iPhone. If we didn’t both use it we’d both have massive phone bills. I even have it in my dock!
It can also do stuff like video, photos and voice messages as well, pretty much exactly like SMS, only they tend to go a bit faster since it can use all the bandwidth of your internet connection.
Anyway, I highly recommend this app. Sometimes you can get it free on the app store, other times it’s 59p, not a whole lot considering how much it saves me!