FAO: people who have a rolling / 12 month 4G sim-only contract for their phone.

WHAT DO YOU HAVE? How much are you paying? Do I really need unlimited data? I'm on a 3G sim-only thing which is just coming to an end and have a new 4G phone. Was using about 1gb a month and I assume with 4G it'll be more but I want to spend as little as possible.

Thanking yous.