I've been looking at going to Bariloche in Argentina for a week in July or August. You can do it pretty cheap if you don't mind staying in a hostel. The hostels I looked at were $20-50 a night depending on if you stay in a dorm or private room. A 7 day lift pass is about $340. I looked into the ovrride packages too but it's much cheaper to do on your own.
I didn't look into Chile that much but I do know there's a $160 visa to fly into Chile, no visa necessary for Argentina. Factor that into your flight costs when seeing what's cheaper.