You often get what you pay for, most broadband with be delivered via a BT line into your home,
then its a case of bandwidth, 512k, 1mb, 2mb, or hopfully some will be 8mb , BT are upgrading some of there exchanges to accomodate the 8mb, I would assume the the cheaper or free offers with be in the lower bandwidth and non exsistent support, ie phone someone in India and keep your fingers crossed !