The league will provide most of the equipment needed for play, including the flags and belts.  You may want to consider some of the following items to help make your child's experience safer and more enjoyable:

Sweatshirt The temperature can get quite cold during the season. Have your child bring a sweatshirt that can be worn under the uniform.

Gloves There's a fine line between staying warm and being able to effectively handle the football. Receiver gloves help to meet both needs.

Cleats Although not required, cleats can help your child change direction more quickly while minimize falling on the moist grass.

There's no need to purchase the most expensive equipment available. Many of the lower-cost products offer the same functionality as those with premium prices, but generally do not include the fancy graphics and gimmicks. Bottom line - be sure your child brings adequate clothing since the weather can be unpredictable.