I will be going to Vancouver this coming 19th Dec and planning to go to Whistler. However, I find the accommodation over there is...so..so...out of my budget. :) We are a family of 7 (6 adults and 2 y.o boy). My budget would be $350/night for 7 of us.
Can anyone advice any other location that I can stay and still can go to Whistler for a day trip?
If I were to stay in Vancouver, is there any bus going there?
Staying in Whistler would be your best bet-- otherwise you are going to end up spending too much time traveling and not on the slopes.
Have you tried airbnb or other vacation home rental places? Those would be cheaper. Also, look outside of the main village. Those will be the most expensive because you're right at the bottom of the gondola. Also, couchsurfer is a great option if you're comfortable staying with strangers.
There is a local bus that can take you into the village, but I'm not familiar with all the stops. Ask your host or concierge before you book.