This bag rolls down to almost nothing and it comes with a compression sack to get it even smaller.  Weighing in under 2lbs it's great for a pack, and its price being almost too good to pass up.

     

      Although it's rated at 44F,  I wouldn't trust it much past mid 50's. (Always add 15 degrees to the rating for comfort) 

 

      That being said, I would still recommend this bag for late spring through early fall to keep you sleeping sound.  I've used it during those seasons and it did me proud.

 

      So...  Small + Light + Cheap = Good enough for mild temps and your wallet.