As someone not from the US, I just had a quick look on Google images. Such a bizarre concept, kinda amazing how different cultures can end up with such ridiculousness.
Well, here in Australia we often used to buy credit for our mobile phones, and the credit was measured in "dollars", as opposed to "minutes". Over time things got inflated to the point where you might pay $50 for "$500" of credit. Then you pay for usage at like 30 "cents" per minute. Of course it costs you much less than 30 actual cents per minute in the end, because "dollars" of credit are not dollars at all.
I don't know whether this ridiculous concept still exists since phone usage is so cheap now that everything except data is unlimited on the only plans I've been looking at, but it was that way for a while.
The US measuring their credit in minutes makes a lot more sense - though having to have credit to receive a text message is pretty bizarre.
