Today's the day, and now is the time! The Apple iPad Air 2 and the Apple iPad mini 3 are now available for pre-order on Apple's website. In the graphic above you can see the full range of prices for the new super-tab(s) from Apple.
Here's a link to Apple's own comparison of the different iPads currently available from them: https://www.apple.com/ipad/compare/
Here are several purchase links for various iPad products: (You can configure each one to your desired color and storage size before purchase.)