I think part of it is that most people probably think that the cost of the useable energy in a battery is a significant amount of the cost of the battery. And s

I think part of it is that most people probably think that the cost of the useable energy in a battery is a significant amount of the cost of the battery. And so they expect that the cost to recharge a rechargeable battery is going to be about the same cost as buying a new disposable battery (or more...the disposable battery maker will be getting their electricity at industrial rates which are usually quite a bit lower than residential rates). And so they think that what you are paying for when you spend 6x as much to buy a rechargeable battery is mostly the convenience of not having to go the store to buy new batteries. But since batteries are sold at the grocery store and at convenience stores and have something like a 10 year shelf life it isn't actually inconvenient to just keep a small stock on hand and replenish them as needed when buying groceries, except maybe for the exceptionally forgetful or disorganized. In fact batteries are a very expensive way to buy energy. Take a 2800 mAh AA alkaline battery. At a nominal 1.5 V that's 4200 mWh of energy, or 0.0042 kWh. If you live in someplace with very high residential electricity rates such as Denmark or Germany that's about $0.0023 worth of electricity. In the US, where electricity is a bit cheaper, for the average consumer it would be about $0.0007. It would take 1400 of those batteries to get the same amount of electricity that would cost you $1 when taken from a wall socket. The result is that for most people they will save money with rechargeable batteries. The exceptions will mostly be people who have very few devices that use AA or AAA batteries. They might go through batteries at a low enough rate that the savings each time they need to change batteries isn't enough to overcome the upfront cost of the rechargeable batteries and a charger.