To ask if this is normal?

[WhyCantIuseTheNameIWant]

Ds is off to big school I September.
Having a read of the mountain of paperwork that needs signing...
£20 for a locker for a year. Plus £5 deposit for the key. And £5 for any replacements needed...

Yes it is normal, kids don't look after lockers/keys properly otherwise and school budgets are extremely tight this year. I would get one, they will have lots of equipment and will be less likely to lose / forget some in the day if locked up until they need it.

DS also starting secondary in September - we've already forked out a small fortune and he's not there yet!! (£10 locker, £10 damage deposit, £10 mandatory art pack, £15 mandatory stationary pack + putting some money on his dinner card as they recommend we do this in advance to avoid hassle on the first day).

Locker essential at the school my daughter attends, as coats aren't permitted on the premises. Stupid fucking rule.