as has already been said, 1k - 100K
I spent £23K in 2018 on a new kitchen, replaced floor/ceiling/new appliances/rewire- CU already replaced/tiled
We used
Wickes top range - but with a 50% OFF offer on units and installation
Doors and windows did not change
In 2007 I refitted a small kitchen myself - did not need require a re-wire, or replaster or floor or ceiling replaced - just laid Vinyl flooring and cost around £3K all in -MFI Units and tiling
also did a bathroom at same time - did not replace the toilet or bath or taps, new sink, units , taps for sink, tiling
total spend for both was under 5K for the lot - but i did everything
A friend around the same time spent £80K for a similar job , just the kitchen , but it was customised / bespoke