It seems the days are gone where people purchase stamps, take mail to mailboxes, raise the red flag and actually mail something. But it's still an option for those who don't feel comfortable paying bills online or through a television remote control.
If you wish, you can mail your cable bill using good old snail mail. You will either be able to pay using a money order, your credit card in which you record the numbers and expiration date on the invoice, or by writing a check and mailing it in the return envelope. However you wish to enclose payment is up to you, just remember to give your payment plenty of time to get where it is going.
If you are mailing a cable television payment via snail mail, make sure you mail it far enough in advance that it will not arrive late, thus adding late fees on to your next bill.