It'd probably be cheaper in the long run to have an app made, rather than sending MMS messages, especially with multi-country customers...
With MMS you'll be paying for each message you send... With an app it's just the one-off cost of having the app developed...
Unfortunately I have quite a few projects on at the moment and won't be free until Mid-February/Early-March. If you still haven't managed to get anything made by then, my services will be available... We can sort out a full spec if that time comes and I'll make sure I give you a good price
