While Android users in Czech, Israel, Poland, and Mexico have been happily buying apps from Google Play for some time now, up till today, devs in these countries haven't been quite so lucky. In fact, they haven't been able to publish any apps, unless they were free.
Today, however, all that changes - Google has decided to expand its list of supported foreign merchants, and Polish, Israel, Mexican, and Czech developers are now included! If you're interested in putting up paid apps and/or in-app products on Google Play, you can sign up now at play.google.com/apps/publish or see whether your country's included in the fun right here.
Source: Android Developers blog