The £21 - £30 free laptop deals, as a category, has the largest selection of free laptops and mobile broadband network operators.
Paying between £21 - £30 for your mobile broadband is the norm to get a free laptop as part of the deal however speeds and bandwidth usage differs by operator and package.
Vodafone has the fastest network and therefore is one of the strongest contenders, however it is worth checking that you can get the higher speed access in your area as not all parts of the country are covered.
T-Mobile offer one of the best laptops in this category although the monthly cost is at the top end of the group, however the estimated RRP against the cost if the first year has the best ratio so in theory you are getting your mobile broadband virtually for free for the first year.