Las Leñas is a self-contained village with about 13 buildings between hotels (mostly expensive ones) and apartments (also relatively expesive). Therefore, the ski bum life is not easy there. You might have some luck in the employee housing building but don´t take it as granted.
Aside from that, you have Los Molles, which is not even a little town... it is more like a builidng/hotel in the middle of the road oin the way to Las Leñas. Usually, there are charter buses going from Los Molles to Las Leñas, and of course, it is cheaper.
Further, you have Malargüe, which is the closest town there is to Las Leñas. You could definetly find cheaper (i mean, way cheaper) rates in more modest hotels over there.... but don´t forget you are more than an hour away of the resort !! Therefore, you´ll need transportation from there to LL.
Aside from that, don´t worry about powderhogs... In LL, mostly in Argentina, there is no rush for powder days ´cause most people tend not to ski on it... so you could find pwder even days after a storm...
And I´m Argentinean!! ja, ja
Let me know if you need further assitance.