I got a free laptop when I signed up for mobile broadband through Three. I needed the mobile broadband but the new laptop was definitely a welcome bonus - I opted for the "mini laptop" as my main one is enormous and heavy, the little one is about average paperback book size and great for carrying around, but they offer a regular sized laptop option too.
That said, it's rather expensive to go for a monthly long-term mobile broadband contract just to get the free laptop that goes with it, and I'm not sure the free laptop would be up to the spec you need, but might be worth checking out *if and only if* you need mobile broadband as well.