1. Simple and clear words are designed on the billboard, such as "3 underwear, 39 yuan, great value discount", which highlights the price advantage and high cost performance of the product.

2. Design three underwear pictures on the billboard, mark the price with eye-catching words, and cooperate with simple advertising words, such as "changing seasons is necessary, high quality and low price".

3. You can design some interesting patterns or images, such as cartoon characters and animals. Highlight the youthfulness and fashion sense of the product, and mark the price and preferential information.

4. Highlight the words "special offer" and "promotion" on billboards to attract consumers' attention, and at the same time highlight the price and advantages of products with pictures and words.