The new Mac Mini starts at $700+ and still requires a separate monitor, keyboard, mouse, speakers etc. Certainly not meant to be portable, so if you're a developer and want a laptop (as many developers do) your next choice is a MacBook which is well over $1k.
You can buy some shitty Windows laptop to make Android apps on for $400. Will it be a good experience? Absolutely not; but at least you can get it done.
Are you talking about the latest MacBook Air, as per the comment, or the previous version that hadn't changed much since 2014? GP is talking about the 2018 model.
You can buy some shitty Windows laptop to make Android apps on for $400. Will it be a good experience? Absolutely not; but at least you can get it done.