Originally Posted by jcborden
The T-Mobile deal is actually better than £1 a month because they don't take your £10, you still have that left so it is actually free Internet for 12 months. After 12 months you can throw the SIM away and buy another, or as I did, top up to £20 and 'buy' 6 months more Internet.
You get 500MB data per month for streaming (youtube etc) and unlimited browsing/email.
Alternatively, if you don't want the hassle of potentially having to contact T-Mobile support (and they don't make it easy) you can buy a pre-activated card for just under £20 (and you will still have £10 credit on this).
You are advised to put the SIM in a phone every six months and make a call/text to keep it active. Worked for me. They currently are only available for the iPhone 4/4S so you will need to get yourself a SIM cutter (or decent knife) and chop down.
I have been using this for the last two years - in a MiFi and now my iPad. I don't think I made a single call/text in that time and never got cut off, but then I don't really thrash data, basically only surfing and emailing. I have seen posts on forums from people claiming to have got gigs of data per month out of this. The most that TMobile seems to have done after the 500MB of data went is to throttle the speed a bit. YMMV as always.
All the TMobile microsims I have seen have a large size chip on them, so cutting these down to nano size requires cutting deeply into the chip itself. Quite worrying if you have not done this before, but it works.