THAT WILL GO LIVE AFTER THE 7th of OCTOBER!!! Sorry for not pointing that out!
Three announced today that it would allow every pay monthly users to upgrade to unlimited data for £3 per month. Their cheapest data SIM Only package (2GB per month) costs £5.11 per month. You can upgrade to TRULY unlimited for another £3 per month. That's less than £100 for a whole year.
This does not apply to SIM Only contracts. See
"Moderator: Sedge on September 28, 2011
@ Rhys – Currently we don’t offer all-you-can-eat data on our SIM only plans. If you want all-you-can-eat data I’d recommend cancelling your SIM 300 (You’ll need to give 30 days notice if you’ve already signed up!) and joining The One Plan or a Talk or Text plans. You’ll need to cancel your SIM only plan by calling 333."