Prepping the garage Options

[AWD DSM 1]

You'll want fiberglass batt insualtion in the walls for sure, R13 would be the best you can fit in a 2x4 wall. For the ceiling you can use the batts again, R19 minimum... the bigger the R#, the better it is at insulating. You could also put a ceiling in and use blown in cellulose. Or there's always the option of having the icyline foam put in - expensive, but nice.

For reference, I put R13 in the walls and R19 in the ceiling of my old 24X28 garage for around $600 in materials. Biggest pain was working around all the crap I already had in the garage, much easier to do if it's empty.