If you are looking for a
Idaho ski resort in the western part, then Tamarack resort is an excellent choice. The speciality of the Tamarack resort is, it's a family friendly four season resort and ice fishing is very popular during winter season when Lake Cascade is frozen. My cousin is living in Sun Valley and I visited his place few years back and got a chance to visit both Idaho ski resorts,
Tamarack and
Sun Valley. As you said, the Sun Valley is bit expensive compared with other Idaho ski resorts, especially renting a place is very expensive.
Vacation rentals at Tamarack is quite cheap and there is a weekend shuttle available from Boise to the Tamarack resort and we paid only $10/person roundtrip, it took us directly to the resort. We got discount lift tickets too, you can even book your tickets online for better deals! All the
Idaho ski resorts offer the best ski vacation for every visitor, but my favourite place is Tamarack. Hope you too like it!