I was on a very tight budget, I managed to do this + underlay for about 150, I found random colour carpet tiles for £25 per 5sqm q bargain and its carpet
Graphic Design Office Carpet Tiles 100 % PP (Polypropylene) Bitumen Underlay Floor Carpet Living Room - China Carpet Tile and Nylon Carpet Tile price | Made-in-China.com
Ultimate Guide To Installing Underlay For Your Carpet Tiles - Prim Mart