You can also pick up pre-paid 4G data SIM cards in eBay and Amazon for between £20 and £30.
These are valid for three months and/or 6GB of data.
They seem to be the result of dealers box breaking modems/USB stick packs up.
They work well - have bought.used a couple myself.
+Steve
[size=2]Steve Gold
PO Box 1014, Sheffield S10 5YG, UK
Home mobie: Telefonica O2
Other UK mobiles: 3, Vodafone, Virgin
Foreign SIMs: Toggle (multi); Germany (Fonic); Poland (Orange PL);
Skype: stevewgold