Originally Posted by
Ominous Gamer
Data and texting plans have been closely tied together for a very long time. You could email my phone, or IM it via AOL, MSN, Yahoo or ICQ, and they all come across as text messages for me. Phones that require extra data plans (paying for a service on top on the default service) usually come with extra features that are absorbed by the data plan, even if the end user sees it as SMS or MMS.
Aside from that, looking into this, not all US carriers act the same, the PAYG government funded phone that Brent has through Safelink does not deduct airtime credit until the message is opened. Tmobile, if I remember correctly used to be the same way (but I've had unlimited texting for years now), but AT&T being the most awesome company out there charges for read/unread, solicited/unsolicited messages.
Over here, most providers have a huge gap in the abilities of PAYG or prepaid phones compared to contract phones.