I browsed the internet trying to find cheap Western charms and the best I could find were at $9.00 each and that wasn't a possibility for our budget, so I decided hand made charms were best. You could buy plastic farm animals, too.
Polymer clay is easy to work with & usually costs around $1.25 for a 2 oz block. It comes in many colors, too or you could blend two colors together to get the shade you desire. If you think you can't make the charms you want, maybe a friend or collegiate could help you. I'd suggest having a picture of the item you desire to make handy, so you can do your best to make your charm resemble it. After a few tries you will get your desired charm, save a bunch of money & have something handmade that your flower girl will love!