On the onion idea, plant a couple of pots in about a 4x4 planter box, preferably off the ground, near your kitchen door, along with basil, oregano, thyme, parsley, and other fav herbs, and you'll almost always have fresh herbs for cooking. And you'll only have to step outside your kitchen door with a pair of scissors for when you need them. A far better method than digging through the bottom of a refrigerator crisper for slimy onions, parsley, etc., and salvaging what you can to cook with. :)
I grow herbs too. I dry them upside on strings, covered by paper bags to keep the dust off.
Free gardening - Do a search for kitchen garbage gardening. It is planting the root parts of veggies you’ve already eaten and planting them in a windowsill. Plant carrot tops, celery bottoms and the lettuce bottoms that come with the roots (out of my price range), etc. You won’t grow a new plant but enough top sprigs to season with.
Save tomato seeds from grocery tomatoes. There is a process to prepare them so do a search. Personally, I’m not buying any fresh produce that can’t be washed, peeled and cooked these days.
Grab a handful of those dried beans you have stocked up on and plant them along your backyard fence. If you have a package of mixed variety beans, even better.