Most of the cost is labour rather than materials. I created our new kitchen, with just the wiring and new ceiling done by others.
I really enjoyed ripping the old one out, knocking down the wall and old ceiling, extending the plumbing and replacing a door with a window. I got exactly what I wanted, including made to measure, solid oak worktops and good appliances. It cost just 5k!
We did have a good temporary kitchen in the conservatory, though - along with disruption, dust, mess, noise etc. for six months. My friend bought an ex-display luxury kitchen for 3k and installed it herself, too, inspired by my efforts.