Have you tried Qeep Mobile Messaging? Well I have and I like the potential!! Its free to use and you can just about do anything with it. I’ve been testing for a while now but haven’t had the chance to post it. You can send messages, upload and share photos and chat. Qeep is downloaded directly to your mobile phone as an app which is totally free by the way as well.
They have been around since 2008 and growing fast. They do offer paid services and messages. I don’t use those at the moment but they are really cheap!
Check it out if you want!