For many goods and services such as electricity, healthcare, cellular-phone service, debit-card transactions, or those sold with loyalty discounts, the price of the next unit of service depends on past usage. As a result, consumers who are inattentive to their past usage but are aware of contract terms may remain uncertain about the price of the next unit. I develop a model of inattentive consumption, derive equilibrium pricing when consumers are inattentive, and evaluate bill-shock regulation requiring firms to disclose information that substitutes for attention. When inattentive consumers are sophisticated but heterogeneous in their expected demand, bill-shock regulation reduces social welfare in fairly-competitive markets, which may be the effect of the FCC’s recent bill-shock agreement. If some consumers are attentive while others naively fail to anticipate their own inattention, however, then bill-shock regulation increases social welfare and can benefit consumers. Hence requiring zero-balance alerts in addition to the Federal Reserve’s new opt-in rule for debit-card overdraft protection may benefit consumers.