well cheapest system will probably be a new sky instal, free box and £33 per month for sports. However, that wont get you the feeds or give you a hobby.
For a choice of sats you need a motorised system, but this gives no guarantees for free footie. Popular receivers are Humax, Echostar, xtreme, technomate, but theres loads more. All do the same and are similar in price. If you want a straight forward easy box then dont get one with built in cam.
Then you need to buy a seperate universal cam to give you choice of encryptions. You also need a decent size dish and a motor to match/cope with dish size. Unofficial cards at the moment tend to be blue titanium, and cams most popular are matrixreloaded or similar. But to get the most choice and go to where the hacks are, you need to be prepared to spend because things change all the time, and one month something works and the next it may not. eg nagravision 30degwest works today, by the end of this week it will not. Last month we had italian sky sports, and this month we do not... etc, etc.
To start you need to spend £400 or maybe £500 for a set up, and spend a lot of time reading
Hope this helps.
L