The expected lows are mid 40's. I have an UQ that I have used as low as 17F, but I'm trying to conserve space in my pack and it's taking up a lot of room & weight. My Marmot sleeping bag that I use as a TQ is rated for around the 30's but again it's what I use when I camped in the teens.
My gear I have available:
Emergency reflective bivy
Grizzly bag liner
Above mentioned UQ.
I've thought about going and buying some 25' x 25" reflectix to replace the yoga mat, but I'm open to suggestions of combinations or alternatives that I haven't thought of yet. Anything I do purchase needs to remain under $30