You'd get lots of good ideas over in S&B.
I spend on average:
Up to £60 on a dress (White Company sales, the odd silk one from Phase Eight sales or from Warehouse)
Up to £60 on a jacket (Hobbs sales are great but I also have some bargain H&M ones)
Up to £40 on a skirt (I like M&S pencil skirts and sometimes get full skirts in places like French Connection, John Lewis own stuff and v occasionally Hobbs NW3 (though most of them are more expensive than I'd pay even in sales and lots of them are too long)
I tend to get plain cowl neck tops to wear with pencil skirts - M&S Autograph and Hobbs - up to £30 a top, or silk tops in Warehouse (up to £45-ish but tend to wait until sales)
I've got 2 Westwood skirts (both sale ones at about £95 each but totally worth it) for days when I want to look a bit more cutting edge!
Heels in Debenhams or Clarks sales (so no more than £40 a pair) and ballet flats from Clarks (up to £40 a pair)
Black trousers for 'period' days (tmi but necessary) - these are a pain. Currently I have an ancient Dotty P's wool mix pair and an ancient cigarette leg M&S pair, but am desperate for new ones.
I'm a secondary teacher (Senior).