It's old news according to the release date posted on the app page in Apple, but today The Washington Post ran a notice that the newspaper is “now available in the app store.”
A complimentary subscription can be had at this link: wapo.st/ipad_app Best bet: Use that link, and don't search and find in the iStore. The link may—or may not—tag your order to get you the complimentary subscription. Searching and finding it in the iStore or via Google Search may—or may not—just get you the free app. Nobody every explains these things in detail on the web.
Here are the Post's boasts about WaPo on the iPad:
Enjoy an "immersive" news experience with The Washington Post App for the iPad. [Features]11 Sections of the paper, including: Top News, Politics, Local & Sports, Rich photo galleries and video from The Post and other news sources, Live Topics, "with numerous takes on important events and the social conversations they inspire."