Blue foam pads are fine for young folks for summer insulation. Two for winter.
Bag examples
Higher end 0 F synth north face $169
http://www.campmor.com/outdoor/gear/Product___58751?cm_vc=PDPZ14lbs 2 oz
Low end 0 F synth slumberjack $59
http://www.campmor.com/outdoor/gear/Product___473214lb 15 oz.
Cheap down 0 F Kelty $189
http://www.amazon.com/Kelty-Cosmic-Degree-Down-Sleeping/dp/B004O706O03lb 12 oz