Ski Gear

Now is the time that most of the Dry Slope centres are having their sales,(ex hire rig outs can cost less than £100, but best be quick most are 1 or 2 day events. Our local 1 is having their sale on saturday (bearsden, glasgow), So if you phone around you may be lucky.

Ali

Specialist ski shops usually do a hire service. Ski jacket and pants should be around £35 for the week. Gloves, sunglasses and goggles can be pricey (£20+ each), but are usually cheaper in resort (where you're spoilt for choice for sport shops), but buy sunscreen/lip cream here to save money.

There are specialist ski hire companies that cater for schools. Contact the party leader to see if (s)he is inviting one to the parents evening, where they bring along samples and offer discounts.
You can pick up thermals and ski hats cheaply here, too. Ski socks should be around £4/pair.

Helly Hansen is a good bet. TK Maxx can be good for ski jackets. You might try Millets, Matalan or - if you can get hold of a card - Makro. I can also recommend the ski gear from Aldi and Lidl - they only stock it occasionally, so keep checking. It's amazingly cheap, but good quality, too.

£500 seems a wild exaggeration to say the least.

Last April I bought a quality 'Head'-brand jacket and ski pants at JJB sports for £50 the pair - not much more than hiring.

Make sure you get two pairs of gloves: one dry pair to wear and one pair drying on the radiator!

other than that:

wolly hat
jacket
trousers

inner layers are a good idea ie fleece

I would reckon you could get it all, in good brands for around £100

Matalan

I got some ski trousers for £3.50 last year.

If it has to be designer my local McArthur Glen outlet has a Tog 24 shop. I got a ski jaket for under £50 recently.