Ensuring Shoppers Transparency in Online Pricing Act of 2012 or the E-STOP Act - Directs the Federal Trade Commission (FTC) to promulgate rules requiring an Internet merchant with annual gross revenue of more than $1 million to disclose to each consumer, prior to the final purchase of any good or service, the use of a price-altering computer program. Defines "price-altering computer program" as one that: (1) accesses a consumer's personal information, including information about the consumer's computer and browsing history; and (2) uses such information to alter the merchant's selling price of a good or service. Allows exemptions to accommodate the reasonable expectations of consumers concerning price changes.
Deems a violation of a rule promulgated under this Act to be an unfair or deceptive act or practice under the Federal Trade Commission Act.