At the Home DePot, Lowes, and such they have these little packets about
three inches square, they call hand warmers. You just snap a little bubble in there and a chemical reaction occurs which generates heat. They shouldn't cost more than 50 cents ea. They are quite thin so they shouldn't feel lumpy, while you walk. If they do, place them under a pair of insoles. Also, I found these amazing angora socks, called "house socks" which feel wonderful on your feet. Warm, soft and silky. I only paid about
$2.00 a pr. CDN. Should be less in US.