I used to have a pair of heavy waders (1,000 gm or 1,200 gm) and they were nice. But they wore out and since then I've bought less expensive (lighter) waders only because the heavy ones cost so much. What I have found to work well is two pairs of heavy wool socks. Look for a high percentage of wool, around 80% or better. Bass Pro Shops has a nice pair for around $10 and they have a lifetime guarantee. If you wear a hole in them, take them back for a new pair no questions asked. Just as important is to not constrict your feet. If you’re wearing two pairs of socks, the outer pair should be looser fitting. Your waders should also be a size larger to give your toes some wiggle room. If you couple two pair of wool socks with a pair of 1,200 gram waders, your feet should be warmer.