Slumberjack Super Guide
30 degree synthetic, mummy with foot vent, packs ultra small (loaf of bread) with included compression stuff sack. On sale in Campmor for less than $80. Only issue is side zip to hip, so getting in and out is a bit of a chore compared to full length zip.
go to campmor.com
they have a ton of sleeping bags. i actually bought the campmor brand down sleeping bag for this past winter. its a great bag and inexpensive.
Ratings
My down bag is rated for 20 degrees. When I did not stay warm, I asked REI personnel. They said bags were rated as if you were going to be wearing a wool suit, so you may want to consider a rating much lower than you think you need.
Mummy styles will hold more heat in, but leave you little wiggle room in the foot area. I have a semi-rectangular I like, because of the room and I can open it up fully on warmer days to drap over me.
-Capri