Title caught my attention.
Hoping someone would know the answer as I looked at this problem about 6 weeks ago. Was after a sim card with a certain amount of data loaded onto it (and easy to top up) and it does not run out. Wanted it for a little 10 inch screen notebook for Dad in the caravan when on holiday over the year. No good paying even £10 and it runs out in 30 days. No good as holiday moght be 4 night maximum.
Same thing as you want.
Was a few vodafone sim cards of an old offer there no longer do.
All the networks here are gready and want money every 30 days but ebay did a few old ones and now can find just this. He will do for £80.
Good if you are going to use for years.
Got dad an external magmount antenna and a beeter wireless N plug in usb dongle and he can use the notebook in the car at mcdonalds car parks and a chain of pubs, greene king.
another way but need to get to these places or find a free hotspot.
BT fon ( peoples home routers, I have) or BTOpenzone another option.
nice to have the 3g dongle and please yourself and will go with what you have bought.
Can now find just the one and not new but ok price. Was around this price the other week.