I was always told you should never skimp on anything that puts you in contact with the ground: shoes, matresses and tires. Alas, being a nerd and being constantly reminded fashion isn't my strong point
For me, £50 was always "decent" and £80-£100 was "saved for best" - might be a bit outdated, as a conversation about work shoes on another forum (not PH, but equally London-centric) had people turning up their nose at anything <£100, and £150 was where it was at to start for something that actually lasts. My working class roots don't let me spend that much.
M&S were my usual, but they've let me down recently....so recommendations are welcome.