Here's some tips for all those out there wanting to put together a SHTF kit or BOB or who are wanting to stock up for an emergency. Wal-mart (if you can stand the huddled masses), dollar stores and thrift/second hand stores have great deals on the things you need. Also, don't be afraid to hit the garage/estate sales. It's rare, but a good deal can be had on something you really need and the person selling doesn't realize they need it, yet. Also wholesale stores like Costco are great for stocking up on bulk items, though you're going to pay more for what you get.
At the local Dollar Tree, for example, I found an eight pack of AA batteries and bottles of hand sanitizer for a buck each. The hand sanitizer can double as a fire starting aid since, being mostly alcohol, it lights easily. It burns with a blue, almost invisible flame.
One thing to consider when stocking up on batteries is that air, while it has a high resistance to electric current, still conducts. This is why batteries go dead in the store while they are sitting on the shelf. One way to combat this is to put them in an airtight bag and pump out all the air. Wal-mart has a hand held vacuum pump for under $7 and the bags to go with it. Ammunition and other items may also be vacuum packed. The possibilities are almost endless.
Water. You can live 4-6 weeks without food, but only 3 or 4 days without water (1G a day/person). I know this for a fact. While I was in the hospital leading up to my surgery, I ate and drank nothing at all for days, the only outside help being the IV in my vein. It wasn't pleasant, but it was manageable. Sources of water are actually easy to find currently. Most stores stock bottled water. Wal-mart has a 2.5G container for under $2. Buy now while it's cheap! I have. In the event you have to go out and find some water, a filtration pitcher or other filtering device would come in handy. Baring that, you can make your own. Activated charcoal granuls are widely available. The savvy survivor could rig up something appropriate. Ten drops of plain bleach her gallon of water should kill most anything that'll make you sick. Always have some on hand. It won't taste very good, and it'll smell like a swimming pool, but it will work.
That's all I can think of for now. I hope this helps someone. :-)
One more thing... If you have any of those orange plastic prescription bottles left over after taking the medicine inside, keep them. Take the label off and destroy it, and then wash them to get rid of the medicine residue. They make excellent water tight containers for matches and whatnot.