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
There are many good videos on YouTube. The lines are sealed with a special end that breaks in a specific way when you connect the lines and tighten them down. And then it’s properly self-sealed.