2. Single Shot 12-Gauge OR 20-Gauge Shotgun ($100).
It certainly doesn’t have the capacity of a pump action or a semi-auto, but a single-shot, breech-loading shotgun will work for a cost-efficient survival arsenal. Again, search for sales or used offerings on gun auction sites. A single shot 12 or 20 gauge in good condition will pop up sooner or later for around $100. A shotgun is a very versatile weapon: You can shoot game birds and have a suitable home defense weapon. Also, 12-gauge and 20-gauge rounds are very easy to find.