https://www.google.com/search?q=android+developer+tutorials&gl=US finds the usual tutorials and the ones by Google are free.

As to the software I use Android Studio. It's a free system and works well. As to the hardware I use an Android phone since hardware debugging is far faster than an emulator. As to the host PC I'd like to see any i7 w/16GB RAM and all SSD but it can run on much less.