Self catering + short transfer + cheap flights is the way to do it. Cheap flights are hard though as you are competing with business people for early/late flights to maxmise your time on the slopes.
As an example Morzine could be done for
Flights £150 pp on Esay Jet to Geneva
Transfers £50 pp (various companies such as Alpybus)
Accomodation £70 pp (cheapo self catering appartment with as many people crammed into a small space as possible)
Ski hire/carrage £50 (assuming you have your own boots)
Lift pass £150
Insurance £10
So just less than £500 pp + any spending money for food and booze.
What he says
You could camp, if you are hardy enough to. I am not sure why you would want to TBH
Keep an eye out on easyjet prices, they do climb a bit in the winter – ways of reducing the flight cost would be to go at less poluar times (i.e not sunday, Monday,Thursday, Friday) Saturday evenings are normally cheap on EJ.
Look at Zurich and going to Stk Anton(2.5 hour train or drive)
Or Andorra (but not from Zurich)
Cervinia from Milano is possible ….