If you grow your own food and don't already do it, start learning to can that food. I recommend a water bath canner and a pressure canner. Pressure canner can process just about anything, but a water bath canner can be a lot more simple. Then you just need pint and quart jars and the two piece lids. Canning salt and vinegar is good to have on hand as well.

Really, canning is a skill that is good to know even if you're not a prepper and grow your own food. We do some mild prepping, but we try to grow a lot of our veggies and don't want to rely on a freezer (we've had one randomly die on us and lost stuff) to store them over the winter.