This is the cheapest way to buy books from online bookstores. Here are some suggestions:

1, compare prices: Before buying, you can go to several bookstores to see the price of the same book and then compare which one is cheaper. This will ensure that your final purchase price is the most favorable.

2. Choose discount time: Many bookstores will launch discount activities at specific times, such as holidays and New Year's Day. There are usually more discounts and concessions during these hours, so you can buy books during these hours.

3. Join the membership: Some bookstores will provide membership services. After joining the membership, you can enjoy more discounts and benefits, and sometimes you can even get free books or coupons.

4. Buy second-hand books: Buying second-hand books in some second-hand bookstores or online platforms is also a way to save money. Second-hand books are usually cheaper, but you need to pay attention to the quality and damage of books.

5. Reduce unnecessary shopping: Before buying, you need to make a list of books to avoid impulsive shopping or unnecessary shopping. Only buying books you really need can reduce waste.