I have to disagree there. In order to get both hbo or showtime would require limited basic and a box. So depending where you are $7.88-$12 for basic service, $15.99 for either premium channel and $1 box fee. Basically $30 to $45 for what you're talking about.
not quite, cable companies have to offer a basic(local) package and can ala carte premiums without any requirements other then basic and equipment. on comcast that would be $10-15 for basic, 3 boxes would be about $16 2 premiums $40 if alacarte or $35 if premier/w2prem so around $60-$70.