Hello Gail,
"I want to stay on the legal side of Apple!"
Good for you! It's refreshing to hear someone concerned about the licensing of softwares as so many try to circumvent it whenever possible.
"found an ebay listing for a new eMac install and update disc and also for 9.2."
Not seeing the seller's listing and description, I can only surmise that they are machine specific disks and should not be used on your G3.
If you could post back with your exact model of G3 I could recommend more precisely what you might want to upgrade to but I certainly would recommend upgrading to Panther or Tiger, if your system specs allow.
You can check for your model on EveryMac.com. It's a great resource for info about your model's specifications and even states the maximum OS that it is upgradable to.
You also can check on FastMac.com for retail install disks. If searching ebay, search for "retail 10.2 install disks" and see what you come up with. Of course substitute "10.3" or "10.4" if that is what you are looking for.
Also, do you need OS 9 disks? Does your machine have it's original install disks?
Post back with further info and comments or questions,
littleshoulders 🙂