I bought an O2 one, simply because I have an O2 PAYG phone. I get a good reception 95% of the time so have very few problems. They're not really PAYG though, you get a data allowance and this lapses when the data is all used or the time is up, whichever is earlier. I pay £15.32 for 2GB for 30 days. This is more than ample for my needs as I download very little and often have unused data at the end of the month. The dongle itself cost me about £40 two years ago. The other alternative is to have a contract, when they will give you the dongle for free, but this may not be what you want if you are only going to use it sporadically. IF you google mobile usbs you will find details of the various offers.