How long is a piece of string?
You can get a simple, elegant, functional grow going for under $2k- and I'm not talking Mickey Mouse either, that's including 2 quality lamps (veg and bloom), a quality blower, ducting, a low-end carbon filter, pots, basic media, and basic quality nutes.
You can do a starter setup for only vegging out plants for outdoors for like $40.
You can set up a warehouse for $20k (although we don't want to hear about it lol).

Somewhere in the middle of all that is something that suits your experience and space...