Installed a mini-split this weekend. AMA.

The pre-charged kits are fairly inexpensive and surprisingly easy to put in, but you'll need about $400 in extra shit.

My extra shit list:

Disconnect box

Surge suppressor

Liquid-tight whip

Lineset chase

20A breaker

Various holesaws

12/3 wire

Caulking

Duct seal

Extra insulation

Wall mount or concrete paving block