I had similar question and after reading what I could find on the site they are leaving the option open to increase prices at anytime but apparently will give advance notice.
This is my understanding as of the date on this post:
1: You can purchase one time payment Annually
2: Accept an annual contract and pay $50.00 USD per month
3: Pay only month to month for $80.00 per month depending could increase to $99.00 per month but I am unsure of this later price, depends on the product I guess. Say Creative Cloud VS stand alone product month to month price.
Until August 31st 2012 there is a promo for owners of stand alone Creative Suite CS3 to CS5.5 for $30 per month for the first year then after that renews at the then current monthly price for annual contract option. As of now that price is $50 USD per month. Look at date of this post and compare prices posted here with whatever the current offering price is, probably has changed if reading this a year or more after inital post date.
