I was also chasing for the cheapest options. Some of the really hyped up ones like satone, insatinternational, sat europe etc. etc. seem to be charging extremely high amounts. I chanced upon this site called smart2check.com which seem to be charging one of the lower amounts. Their digiboxes are on the higher side but their sky monthly deals seem to be much better (at I think some 50 pounds one time fees), which seems to be one of the much better prices after seeing all the 100 plus prices around. I have not tried it myself but just came across this site, so thought will share with people.