I have an inexpensive sleeping bag, I use ABCO Tech for all seasons. In winter, it's probably cool, but in the fall and spring it fits perfectly. If you need to choose a really best backpacking sleeping bags under 100 , then you need to look for articles with reviews of different sleeping bags from professional tourists. I usually find a lot of useful information, full characteristics and an honest opinion on the Internet on portals about hiking and camping. It really helps to choose the best option for me.