Only relevant for very occasional mobile broadband users that are after a secondary means of access.
The benefit is that with this Vodafone package
* remaining allowance doesnt timeout after a 30 days (unlike other networks offerings and) so could last you for 2 years if need be.
* no contract
In the Vodafone shop today they are offering an extra 1GB (worth £15) topup for the same price as the dongle+1gb allowance.
Further topups are £15 for 1GB.
Really good package for occasional/light usage (i.e. holidays and occasional train journeys) where this is NOT your main method of accessing t'web.