T-Mobile UK Web 'n' Walk HSDPA 3G BROADBAND data SIMCARD

[Motel75]

Makes sense, really. The standard TMO prepaid data rate is capped at £1 a day up to 40 MB, but if you go above that, they start charging you £4 per additional megabyte. So if 40 MB isn't enough, use a second SIM and again pay £1 for up to 40 MB. (And if 80 MB isn't enough... you get the idea.)

In other words, it's a standard UK T-Mobile SIM card (not a specific data SIM). Don't bother with this eBay seller. If you're coming to the UK, they often give away SIM cards for free, or if you buy one in a shop it will be very cheap or include a subsidized phone. Topping up (ie, adding credit to your account) is really easy, you can do it at almost any supermarket and lots of other places, and there are several methods (code from a scratch card, etc.).