Currently the best you can get is Coinbase . They offer SMS service that works with any phone or network (more info here https://www.coinbase.com/sms_service?r=53d63ba9fc7964914600000b). After verifying your number and setting up a PIN simply send a text using one of the preset shortcodes. If you are an existing Coinbase user, you need to enable SMS access in your account (see supported countries https://www.coinbase.com/global?r=53d63ba9fc7964914600000b). Please note that you can send an SMS to buy bitcoin with Coinbase, but they will debit your primary bank account not your phone bill!