Depends where you purchase them. You can find some cheap ones for a dollar at a 99 cent store.
They both involve batteries.
Too much. Get a battery are Walmart. They are quality batteries at a decent price.
1.2 volts
a AAA battery. Or a watch battery, or a AAAA battery, or any number of battery types. http://en.wikipedia.org/wiki/List_of_battery_types
A standard AAA battery typically has a voltage of 1.5 volts. This applies to alkaline and zinc-carbon AAA batteries. Nickel-metal hydride (NiMH) rechargeable AAA batteries usually provide about 1.2 volts.
Many different battery brands include AAA batteries some examples of AAA battery brands include two of the biggest battery brands, Energizer and Duracell.
chemicals
What are the ingredients in a AA battery?
why do aaa batteries overheat
alkaline AAA = 1.5 volts
I just paid 131.00 for aaa to come out run the test and change the battery for me.Comes with 6 year warranty.First three years free of charge next 3 years prorated.
AAA is the size of the battery, there are many types and makes of AAA battery and the shelf life for each is different.