Muffin Top Merkley
Be a man!
Kinda depends on what you're into, if you read alot of Marvel, for about $10 a month (I beleive) which is a pretty good deal, DC does day & date digital, which means as soon as a comic hits the stand it's available for DL on ComiXology, however if you wait a bit they drop the price of each issue from $2.99 to $.99. There is another site, Graphicaly, you can use to read stuff online from all sorts of publishers.
I just checked out the Marvel site, it's ten dollars a month, or sixty dollars a year. I can't seem to find anything current at all through, but it still might be worth looking into for past events.