Start with a "brick" of .22LR HP (10 boxes of 50 in their own small boxes); these rounds could become better than gold for barter and are great for rats, pack dogs, and can be enough to discourage human predators. So why not get a 4" .22LR such as a S&W J-frame or larger K-frame revolver or a Ruger Single Six.
Also buy 2 boxes each of the "standard cartridges: 9mm, .38 Spec. +p, .357, .40S&W, .45ACP, and 2 3/4" 12 Gauge "turkey loads" also for later use or barter as a last resort because you alone failed to prepare to defend yourself.
Surviving is a dirty business - YOUR responsibility alone. Plan on surviving for > 3 months with no outside help. Protect the weak around you. Get a handgun with a quality holster, hip, ankel, or shoulder, to always have your pistol/revolver with you and a shotgun with sling AND with the FReeper Rule of 1,000 rounds for each weapon even if in same caliber because one day these survival tools may well be "SOLD OUT" or outlawed.
Every household must buy non-hybrid seed for "survival vegi-gardens" which may become turf over which close quarter combat may become necessary. FYI: corpes make bad compost; don't use your own.
Start with a "brick" of .22LR HP (10 boxes of 50 in their own small boxes); these rounds could become better than gold for barter and are great for rats, pack dogs, and can be enough to discourage human predators. So why not get a 4" .22LR such as a S&W J-frame or larger K-frame revolver or a Ruger Single Six.