Where I went to secondary school the prices were:
Blazer: £95
Tie: £6.50
Pullover: £27
Trousers: £30 (you had to wear the school trousers, which had a little LO embroidered just below the waistline, next to the pockets)
Bag: £25 for school bag, £7 for PE bag
PE Kit (vest, shorts, socks): £27.50
Rugby Kit (jersey, shorts, socks): £42
Other bits (Apron, Swimming Trunks): £13
For a Grand total of £273
Needless to say that the white shirts, black 'proper' shoes and grey socks were bought from elsewhere! Everyone bought one set of everything and stuck with it until the blazers were halfway up their arms and the trousers became ankle swingers before buying their next set of uniform. I think I made it through secondary school with about 3 sets of main uniform (Blazer, Tie, Jumper, Trousers), 2 sets of PE Kit and 1 set of Rugby Kit and then one more set of main uniform for Sixth form (with the Blazer costing about £20 more than the secondary school ones.)