They often use third-party intermediaries to adjust those prices.
You can protect yourself by using a VPN, clearing browser cookies frequently, browse in Incognito mode, and compare prices.

Maryland, New York and other states are moving to require disclosures anytime personal information is used to dictate pricing.

From Wikipedia – Update:

Walmart's Role
Walmart is among the retailers adopting electronic shelf labels, which could facilitate surveillance pricing. This technology allows for real-time price adjustments based on consumer data, raising alarms among lawmakers and consumer advocates about potential exploitative practices.

From EPIC:

Recently, Kroger caught the attention of lawmakers and the media over its potential use of facial recognition to enhance its surveillance pricing capabilities and its use of electronic shelving labels (ESLs) to profile and target customers with higher prices. Although Kroger has since claimed that it has no plans to identify customers' faces at digital displays, the grocery chain has been using ESLs for years.

A customer published a post on social media that Jet Blue airlines increased the price of a ticket by $230 in one day and that he was just trying to get to a funeral. Jet Blue posted this message in response, "Try clearing your cash and cookies or booking with an incognito window. We're sorry for your loss." Jet Blue was then accused of surveillance pricing. Jet Blue denied the accusations and deleted its post.