The fourth-generation iPad Air is an excellent device that leaves the older design of the base iPad and adopts that of the iPad Pro. Right now, it's also on sale at Amazon. The 64GB iPad Air 4 is $570 (was $600) and the 256GB iPad Air 4 is $680 (was $750). Those aren't the biggest discounts in the world, but Apple products rarely go on sale for less.
All five colours are available at Amazon right now, though the silver version is only available with 64GB at this moment. I currently own the 64GB model, and I've found it to be plenty of space, especially if you use it for entertainment purposes. Netflix, other streaming services, and even your iTunes Store purchases can be streamed, so you don't actually need to store your library on the device. Unless you want to save a lot of high-quality photos, use the iPad Air for work, or play a lot of games, you'll likely be good with 64GB.
If you're looking for iPad Air 4 accessories, there are two major ones that are worth getting depending on how you want to use the device. The Apple Magic Keyboard is currently $200 (down from $300), while the Apple Pencil 2 is $125. The keyboard helps turn the iPad Air 4 into more of a laptop-like device, while the Apple Pencil 2 is great for artists and can be charged by connecting magnetically to the side of the iPad.