if you are planning on buying it you can get the whole adobe suit for about 50$ a month. you get 100gb of cloud storage also, and fast updates about every month or so.
http://www.adobe.com/products/creativecloud/buying-guide.html
you might be interested in the Creative Cloud — Photoshop Photography Program you get
Special single app pricing on Photoshop CC. Hurry — limited-time offer.
Latest version of Photoshop CC plus Adobe Photoshop Lightroom and Bridge CC
20GB of cloud storage and a Behance ProSite
Requires annual commitment; billed monthly