Apple adjusted their iPad lineup this week. They discontinued the Air 2 and the Mini 2, and replaced them with a new, lower priced version ($329), which is now called iPad. They still have the mini 4, but I don’t see that sticking around, unless they release an updated version, without a number.
I believe these are the only two that Apple wants to have. The Pro is for power users, and the iPad is for everyone else, at a price that’s as cheap as it’s ever been.