The Second Female Lead Gets Rich Selling Goods Between Two Worlds

Straightforward blurb:

Yu Xiuli accidentally transmigrates into a period novel as the second female lead. She also gets a System that lets her travel between the 1980s and the modern day to trade goods, using the difference between the eras to make clever exchanges. From scarce supplies in the 1980s to modern high-tech products, she accurately reads the market, and every deal multiplies her fortune. As she changes the course of the story, Yu Xiuli becomes not only a hidden tycoon but also the leader of a business revolution spanning eras. Hers is a rags-to-riches legend woven from courage and wisdom.

Theme: Save yourself