Insulation questions

[TAftw]

I eventually want to insulate my 22x24x10 2-car garage. It's already sheetrocked, and the roof is enclosed except for a 3x3 hole above the door opener, which I could cover up. I used blow-in insulation at my sister's house, and I think that's the route I'd want to go. My questions:

1. How many of these packages of insulation will I need for the walls?
http://www.homedepot.com/Building-M...splay?langId=-1&storeId=10051&catalogId=10053

2. Is it completely necessary to insulate the ceiling?

3. Am I looking at the cheapest way to do this?

4. Are there any more cost-effective ways this can be done?

Thanks a lot!

 

[Shocker]

1 - Chart shows 9.3" installed, 8.4" settled for R30. 21.7sqft per bag = about 24 bags.

2 - Yes, if you are going to heat the shop and use it in the winter.

3 - 24 bags x $11.39 = $273.36 plus the cost of the blower and vapor barrier.
R30 Owens Corning unfaced is .30 per sqft = $158.40 plus vapor barrier.

I think #3 answers number 4.

It would be cheaper to use the OC fiberglass. You might be able to get it cheaper if you look around. Those numbers were from Home Depot.