Some of the gameboy games had batteries that have all started to die in the past five years
Speaking from experience, you have two or possibly three routes to take.
Most Game Boy games use the 1616 battery (going from memory here, but it is a common one) so if you get the batteries and the proper bit to open up the games (don't cheap out and use an improper bit you'll fuck those plastic carts up with metal tools) you can simply remove the battery and replace it which will nuke your save file. That's option one and maybe you don't want to lose your saves. I didn't!
So options two and three preserve your saves.
Option two involves performing what amounts to a battery bypass in which you provide power to the cartridge in the form of another battery while you replace the actual bad battery, then put it all back together while maintaining a continuous circuit and you've replaced your battery, saved your files and are essentially qualified to perform heart surgery on living humans.
Option three is more expensive but easier. Grab yourself a tool to connect your cartridge to your computer (if memory serves the retrode has a GameBoy attachment and there are other devices out there) and once you've done that you can pull your save files onto your computer, replace the battery and then move the save files back onto your cartridge. A tool like this also gives you the opportunity to dump your cartridges as ROMs on your computer, giving you honest to goodness legal ROMs.
Let me know if you have an interest in any of this. You can send me a very gay PM through the forum's totally safe and non-hackable private message system.
These methods are also applicable to pretty much any cartridge-based media that uses a battery save.
Regardless of what you think about ROMs and piracy and all of that, there is a lot of opportunity to refine some basic technical skills that may prove useful in your personal and professional lives. I strongly encourage anyone that is able to tinker with their toys to do so. You cannot predict how far it might take you.
With regards to some of my older stuff, things like Pong machines and arcade cabinets
will lead you down the road of learning how to solder and desolder and once you've figured out how simple printed circuits actually are and they lose their intimidation factor, the sky is the limit. You can pretty much repair
anything around you for pennies.
Throw in some welding skills and the ability to machine and you'll almost be qualified to work on pinball machines.
