While there is no public sign-up for our test servers yet, we occasionally give away accounts to fans. Make sure to subscribe to the newsletter and to participate on the forums to not miss such an opportunity.
We think that the browser is a very capable gaming platform, available on pretty much every computer in the world. It's the perfect match for the kind of play style we have in mind, allowing people to play from their office or next to doing something else without having to download, install and run client software.
Nothing is set in stone yet, but we expect the most commonly used payment methods to be available from day one. This includes but is not limited to PayPal, credit cards and paysafecard. Since we roll our own payment systems, we can add new payment methods over time.
Properous Universe is most and foremost a browser-based game. While we do have plans to provide a client software that could be offered on platforms like Steam or the Apple App Store, this is a low priority for us right now.