Had a phone call yesterday from a T-Mobile rep, he stated that they currently have an offer open for existing customers as follows.
Free USB Dongle,
Unlimited downloads I asked if they had a fair usage policy or any limits imposed on downloads and was told no definitely not.
£10 a month for existing customers.
I forgot to ask how long you had to run this for Doh but suspect you will be tied down to an 18 month contract to get this price.
This offer is not on the website or rather it is at £15 I believe, you have to phone 150 to get it at this price.
I asked the guy to phone back next week to discuss as my contract is up for renewal and I want to see what they offer me before I decide to stay with them or not for another year.