Does this make any sense? (Picture messaging with Sprint)

So I've had picture messaging with sprint for a number of months now, and I was always under the impression that it would only cost five dollars a month. However, I talked to two Sprint representatives yesterday, and they said the five dollars a month I'm paying is only to ALLOW my phone to be able to send picture messages, but the actual picture messaging costs three cents per kilobyte, which, each picture is roughly 224 kilobytes, translates to around $6.72 PER PICTURE. So I'm paying five dollars a month in order to be able to picture message, but then for each picture I'm paying roughly $7. Is that messed up or what?