引用自 Anonymous Helper：

The problem is law states that Valve charge you exactly the advertised price, nothing else. This is to protect consumers from stores that advertise one price and charge different price at checkout.

This topic has been discussed to death in the Suggestions / Ideas sub forums. Just do a search and you find dozens of similar topics there.

Federal regulations prohibit "bait and switch" advertising under the FTC Act's prohibition against unfair or deceptive acts or practices (15 U.S.C. § 45), but enforcement is primarily the responsibility of the Federal Trade Commission (FTC). The FTC has also issued specific rules like the 2025 Rule on Unfair or Deceptive Fees for event tickets and lodging, and the 2023 Combating Auto Retail Scams (CARS) Rule for new car dealers, to combat bait-and-switch tactics and hidden fees in those industries. A bait and switch occurs when an advertiser lures consumers with an attractive offer they don't intend to honor, only to switch them to a less desirable or more expensive product.

Consumers cannot reasonably avoid injury from an act or practice if it interferes with their ability to effectively make decisions.Withholding material price information until after the consumer has committed to purchase the product or service would be an example of preventing a consumer from making an informed decision.

引用自 Anonymous Helper：

Every country has it's own version of it and US has both federal level and state level laws about it.

Federal regulations prohibit "bait and switch" advertising under the FTC Act's prohibition against unfair or deceptive acts or practices (15 U.S.C. § 45), but enforcement is primarily the responsibility of the Federal Trade Commission (FTC). The FTC has also issued specific rules like the 2025 Rule on Unfair or Deceptive Fees for event tickets and lodging, and the 2023 Combating Auto Retail Scams (CARS) Rule for new car dealers, to combat bait-and-switch tactics and hidden fees in those industries. A bait and switch occurs when an advertiser lures consumers with an attractive offer they don't intend to honor, only to switch them to a less desirable or more expensive product.

The actual legal documents are written in legalese and not that easy for a layman to read.

https://www.federalreserve.gov/boarddocs/supmanual/cch/200806/ftca.pdf

Consumers cannot reasonably avoid injury from an act or practice if it interferes with their ability to effectively make decisions.Withholding material price information until after the consumer has committed to purchase the product or service would be an example of preventing a consumer from making an informed decision.