+/- 5 degrees means nothing with respect to sleeping bag ratings. In fact the "ratings" are very subjective. I have a "45-degree" synthetic bag that I seldom use because I sleep cold and cannot even use it in 55-degree conditions. I only use it for coastal hiking where temps stay about 60 degrees day and night. If you have to take extra clothing to sleep in then there really is no weight savings in getting a 45-deg bag. I am with Lori- find a 30-degree bag of the same weight. As for budget- tighten your belt in other areas- when I was a poor college student I invested in top-dollar gear by eating beans and rice for a month, giving myself haircuts, not driving a car, and living in a dump. It is all a matter of priorites.