They didn't have caps, but I was billed per minute. Ah, the joys of rural living, paying exorbitant amounts of money for a 56k connection that in reality was closer to 14kbps. Oh, and the line was such poor quality that it would fry modems and cordless phones regularly. We never were able to get that fixed, I just kept a spare modem around, and we went back to basic analog phones that would likely survive a nuke blast. Dial-up tones cause my eye to twitch to this day.