There are a multitude of websites that already show one how to save their tomato seeds, but I thought I would show you how to do it anyway!
I know that you will see the Sungold listed there and it is actually an F1 hybrid. I have saved seeds from them before and have obtained nearly the same fruit the following growing season. Maybe I haven’t scientifically done a test to see if the size and taste is similar, but to me it was close enough to call Sungold and be happy with. I want to say I’ve grown at least to an F3 generation of them out. When I get my seeds back from storage (hopefully in about a month…after 2.5 years in storage!) I will try my old saved Sungold seeds and see how they grow. It is always fun doing some experimenting.
As for what to save your seeds in, you can use regular plastic baggies or order special seed packets online, but I found these jewelry bags at Hobby Lobby (whatever craft store of your choosing should have something similar) and they work great! We have previously used paper seed packets that have a seal you have to lick and then if you opened them you’d have to tape back shut, but I like the zipping seal on these.
It really is that simple. Just put aside some space on your counter and you’ll be saving seeds for next year!