If there was a chart of this kind of thing or a solid non-SEO-spam resource, that would be helpful, too.
if you have space, chayotes aka mirliton are pretty easy to grow. Versatile to cook with, stir fries, soups, stews etc. They store well over winter. Here’s a good site devoted to growing them.
I grow a lot of peppers but this year has been very annoying with ants farming aphids on them, it’s a constant battle. Eggplants, on the other hand, just grow here without any effort. Put them in the ground or a good sized pot, make sure they’re watered daily, and eat those beautiful purple bastards. I usually do Chinese eggplant or fairy eggplant.
Edit: they’re also really pretty with giant rich green leaves and the iridescent purple fruit
Seconding tomatoes. You may need a tomato cage or a couple bamboo poles and string to support the vines but nothing fancy. They grow well with basil too.
If you like hot peppers, grow them too- and make your own easy salsa.
The answer to “what cuts my grocery bill” raises the question of what groceries you buy. In general, small-scale farmers/gardeners who make a living off a limited plot of land tend to gravitate to leafy greens, because market prices give those the most revenue per square foot.
Seconding herbs but grow your mint indoors. Rosemary (once established ), thyme, and dill are consistent and useful to have around.
Seasoning herbs like mint, sage, parsley, cilantro, lemongrass, green onions (you can cut off the green parts a couple times and even replant store bought green onion after using the greens). All of these can be grown in medium to large pots and mint and sage in particular grow like weeds (mainly cuss they are descended from weed like plants). Pumpkins and squash are another good one, especially butternut squash which can be cooked in a variety of ways. Homegrown tomatoes are also awesome to have and experience compared to supermarket ones (grew several varieties this year and they were great especially cherry tomato varieties).
