Actually, in some cases, alkaline bats are same price or cheaper than rechargeable. How this comes? Easy. You may get 8 pairs alks AA for 1.5 euro. Rechargeable are more expensive, about 4 euros for 4 bats. Alkalines cost 0.18 cents each, where rechargeable 1 euro each.
So, you need to recharge the batteries at least 4 times to have match price correct? WRONG.
Alkalines will last more than 2 times as a rechargeable. So you need to charge 8 times to have price match e correct? WRONG, again.
Rechargeable batteries will lose 10% of it's capacity in the first 24 hours, even without operation. From then on, they lose about 10% per month and that is not so bad, but consider that alkaline batteries will last up to 6-8 years!!! So, in some cases, alkaline are... priceless

And of course, do not forget that, unless you charge rechargeable with solar power or wind power, they do not charge for free. Every time that you charge a battery you use double the power that will provide (due to thermal)...