While I personally wouldn't use the ChompSMS pay per message option because of unlimited messaging, I would highly recommend the international SMS option, with this feature users buy credits that can then be used to send messages to several supported countries (The list is growing).
Here's a list of Internationally supported ChompSMS countries and their SMS Costs:
- AUD - 10 Cents
- CAD - 10 Cents
- CHF - 12 Centimes
- EUR - 8 Cents
- GBP - 6 Pence
- HKD - 70 Cents
- JPY - 10 Yen
- SGD - 12 Cents
- USD - 10 Cents
As I mentioned before the U.S. rates for U.S. Customers may not be all that great considering many users have text messaging and even unlimited text message plans. However the ability to send worldwide adds a new element to SMS'ing. I personally like that I could buy a certain amount of credits and after each SMS know how many credits I have left, its a great way to make sure you don't over budget the number of Internation messages you send.
There is one additional cost that could possibly be incurred by users and ChompSMS makes sure their users know about it. Here's the special note they put below their messaging plans:
"Please note: When you choose to send an SMS message via chompSMS, it uses your Internet data connection (WiFi/3G) to transmit the message. Usually, using this Internet data connection doesn't incur additional charges. However, some providers do charge you for data usage (depending upon your plan, limits, etc). As an indication, one MB is enough to send around 1,000 chompSMS messages (depending on the text size)."