Try to find heritage seeds instead of the cheap stuff that might not produce viable seeds for the following season. Yes, put your packets in a sealed jar and store it in a cool area like the fridge.
I’m starting to save seeds from produce that looks like it’s of quality and locally grown. Of course, whether they’ll produce is anyone’s guess but I’m not letting anything go to waste these days. It doesn’t cost any $ or time letting them dry in the window.
You can buy all the beans in the store and plant them. I have a store of them either to eat or plant and most dry variety beans can be picked and eaten green too.