The only way to make that shit pay is to groom a cult to do it for you, large-scale.

They're called grand parents

I still buy the vast majority of my own food, but:

I've been eating the same $0.99 bell pepper going on three years now.

A $3 packet of jalapeno seeds has made a year's worth of taco tuesdays.

I'll never buy Mint again; I couldn't get rid of my patch of peppermint if I wanted to.

I can grow much better tomatoes than what you'll find at the local mega mart.

A $3 packet of okra seeds will thicken a year's worth of gumbo.

My little vegetable garden, which is smaller than my living room, yields somewhere in the neighborhood of 100 pounds of produce every year.

Growing your own greens and herbs is super easy with a hydroponic setup, but obviously you have to invest the time into getting it set up. There are a lot of pre-made options available these days, though, so it's not as much work as it used to be even just a few years back. Saves me a lot of trips to the grocery store.

Eh, it really depends. I assume you don't mean all your food needs here. It's pretty easy in a lot of climates and situations to supplement nutrition and/or flavor by growing even one or two plants. Source: grew peppers, spinach, etc. on my tiny tokyo apartment's balcony and would gift friends whole plants to put on their balconies/windowsills for the same and now do small-scale farming in rural north Japan.

The only thing I've successfully grown is tomatoes. And they tasted weird.