Dealing with winter. I live in the rural upper Midwest, where winter can hit -20 with whiteout blizzards, week-long power outages, and car-burying snowdrifts. I’ve seen too many people move here from warmer places and think “I guess I’ll buy a warmer coat and a snow shovel”, rather than “I should have a backup generator, a backup heat source, a few barrels of spare fuel, a month’s worth of stockpiled food, and at least two different pieces of heavy snow-moving machinery tested to be in good working order”.

Bug zapper flyswatter. Like you can buy at Harbor Freight for a few bucks. It might not be a terribly effective solution to the overall fly population, but in terms of grim-bloody-vengeance-per-dollar, it’s one of the best investments I’ve ever made.