How to mod my saturn for backups?

[endrien]

I just picked up a us region saturn(I'll probably region mod it as well) and I would like to mod it to play backups. I've seen the mod chips and there roughly 24$ but is there any other way? Also how long will a new battery last in a saturn(Thats how it saves right?, much like a gameboy game)?

Saturn model MK-80000A