To purchase good quality popcorn boxes, you should consider the following factors:

1. Material: Look for boxes made from high-quality materials such as sturdy cardboard or food-grade plastic that can withstand the weight of the popcorn and maintain the freshness of the product.
2. Size: Choose the right size box for your needs, taking into account the size of the popcorn and the portion you want to serve.
3. Design: Look for boxes that have a appealing design that will attract customers and enhance the presentation of your popcorn.
4. Quantity: Consider the number of boxes you need and purchase a bulk quantity that will meet your requirements and provide a cost-effective solution.