There's a good chance that young kids have almost everything involved in a cowboy or cowgirl costume already in their closets. Toss on a pair of jeans and a plaid shirt, and children are halfway to finalizing the country costume. Kids' cowboy hats are easy to find and generally cost less than $10.
Vests, boots and bandanas also make for cute finishing touches to the outfit. Finally, a yellow or gray construction paper star can turn a plain old cowboy or girl into a sheriff!