The batteries the gshocks use goes for about $15 or less.

Regular batteries may be a better deal but that doesn't include the process of opening the watch, replacing the battery, and then resealing the case.

I'll trade $15 and a 15 minute job once every 15 years for a 15 minute job every 5 years. And no watch with a regular battery will have auto-backlight (for the obvious reason).

And also... if you want a deal, don't buy a $100 watch with auto backlight, capable of setting its own time off of a radio, and capable of ringing your phone when you can't find it.

F91W will do! That's why they're so popular!