Do cell phone services price gouge text message prices? You judge.

Lets make some educated guesses and side conservatively on the numbers.

Voice sound quality 96kbps (I'd think this is at least 128kbps but I don't know what compression or other tricks they might use so I'm siding on caution)

Going to use a T-Mobile individual plan with 1500 minutes and 300 text messages. I chose T-Mobile because they are considered one of the less expensive services.

(I'm going to assume the protocol overhead between data and voice is similar so I don't have to look it up)

T-mobile highest non-unlimited voice - 59.99 ($60) (1500 minutes)
T-mobile highest non-unlimited message - 4.99 ($5) (300 messages)

Messages:
300 Message * 140 Bytes/Message = 48,000Byes
48,000Byes / 500 (pennies) (rounded) = 96B/cents

Voice:
9600bps / 8 bits = 1,200Bps
12,000*60 = 72,000Bpm
72,000Bpm*1500minutes = 108,000,000Byes
108,000,000Byes/ 6000 pennies = 18,000B/cents

Ratio:
18,000B/cents / 96B/cents = 187.5X more expensive per Byte

I just came across this after writing this post.