Beware of moonshado unless you're sending marketing messages - their support pages state that all texts sent from them have this footer: "Msg&Data rate may apply txt STOP to opt-out". Not something I'd want if your users are paying to be sent messages (like with this service).
I'm looking at using CDYNE for texts. At volume they also charge 3c, but there's no distinction between networks with their price so you pay the same to text Nepal as you do San Francisco.
Thanks for the tip. So far the texts have been 'clean' - no extra stuff, but I'll keep an eye out for that. The reason I went with them is that you pay $20 for 20000 credits and I thought it was a credit per SMS, but it's actually around 29 credits per message. Another person mentioned twilio- it's the same price but looks like it has some other nice features.
Yeah their credits are a bit sneaky :) Twilio only supports US numbers which is a problem. If you're looking at telephony companies, Tropo (https://www.tropo.com/) is only 2c per message and sorta supports international numbers. Their 'support' is basically "if it works, awesome, if it doesn't, well we never said it definitely would". It's worked well to Australia for me so far. International support is coming at some point, though I don't know if it will still be at 2c per message.
I'm looking at using CDYNE for texts. At volume they also charge 3c, but there's no distinction between networks with their price so you pay the same to text Nepal as you do San Francisco.