Once you start adding up the various services and tiers for each one (in some cases), it can vary. It will obviously be a lot less than your cable TV service if you have the bells/whistles and not basic cable.
Best method is to visit each services' web site and write down prices on a piece of paper for a comparison to your cable bill.
I am considering getting rid of my cable subscription. I currently have a blu-ray player that gives me access to the internet, I really haven't used it much and am not sure what content is available, what is free and what costs extra. And for those services that cost, what ball park costs are there?