Sony CR2032 Lithium 3V Battery 10 Pack .38¢ each

[trs96]

If you buy a lot of older PCs and refurbish and hackintosh them, these are good to have available. If you have some 6-9 year old computers that still work, it's a good idea to change these. At 38 cents each, a real deal. They will last longer than 3 years "on the shelf" too. These are otherwise known as CMOS batteries. Work in any motherboard. I like to test them when new to see how "fresh" they are. If at 3V or below, put it into a mobo CMOS socket and plug it in to charge them up. Put back in storage for a few more years. Fresh new CR2032s should read about 3.4 to 3.5V on a multimeter.

https://www.amazon.com/dp/B0042KOJRE/?tag=tonymacx86com-20

 

[trs96]

If you only need 5 batteries right now, these are the best deal on Amazon. $2.25 makes a good add on item when you need a little more to get free shipping.
https://www.amazon.com/dp/B00K62Y2O2/?tag=tonymacx86com-20