Beginner Gardening: What's eating my garden, &how do I stop it?, 0 by Dilettante

Dilettante wrote:
Last year I started an organic strawbale garden using tips from these forums, and grew tomatoes, squash, parsley, and peppers.

This year, I planned ahead better, and started peas and spinach inside. But when I transplanted them outside, something kept eating the spinach leaves. Some of them look chewed off by an animal, others have holes.

I had read that marigolds deter bunnies, and I had started marigolds and zinnias inside, so last week I transplanted the flower seedlings, hoping to deter the bunnies. I also rigged up a twine that runs around the edge of the bales, about 4 inches from the top edge of the bale, and tied strips of shiny mylar wrapping paper to the twine, the mylar makes a crinkling sound in the wind, ansd reflects any ambient light, even at night.

But the next day, something had eaten the marigolds down to the base, and some of the zinnias were missing most of their leaves.

I can't afford an expensive solution right now (no fencing or motion-detection security lights!). I don't own a gun, and I don't want to spray pesticides (in case the holes are made by bugs). Is there anything cheap or free that can deter whatever is eating my garden? Last year I lost some tomatoes and parsley to critters, but they didn't take much, so it wasn't a problem. This year I have put much more time and money into the garden, and I don't want to lose all of it to the neighborhood pests.