as long as it's not cellular. cellular service in the usa is a rip-off. last mile infrastructure costs are a fraction of a fraction of what copper service costs, and as you say, the long distance is virtually free. add to that the insult that sms is contained within the headers of normal "here i am" beacon traffic, i.e. no special broadcasts or routing required so no costs incurred in providing, and you start to get the picture of what i mean next time you pay $5 for 200 of the things...
if that perspective doesn't work for you, consider that third world nations cannot afford copper, but they can afford cellular...