looking for somewhere within a reasonable distance of Zurich airport [already found reasonable priced flights] ...
Flims looks like a good location - it is about 90 minutes drive, has a reasonably snow record, and there are other resorts within a short drive, in case of poor conditions on the local mountains ... and it even has "backpacker" accommodation ...
the price of flights would be approximately 170 gbp
the price of car hire would be approximately 35 gbp per person
the price of accommodation and breakfast could be as little as 84 gbp
the price of the top ski and boot hire would approximately 100 gbp
and the price of the lift pass would be approximately 82 gbp
so the total price, before petrol, dinner and alcohol would be 470 gbp