We study the impact of price expectations on converting consumers’ planned purchases into actual purchases in a store and investigate when and how the effect of one type of price expectation dominates the effect of another. This is the first marketing study to disentangle the two effects. The major reason for the absence of such studies is the identification problem. Since price expectations are unobservable and both explanations can lead to the same observable outcomes, as the above. To overcome this data problem, we designed a laboratory experiment where participants shop at an online store under a realistic environment, in which they make actual purchases by spending real money. This experiment enables us to collect detailed information. Specifically, participants first report what product items they plan to purchase and how much they expect to pay for those items in the store, before they are exposed to actual prices (we label this as PRIOR). After the shopping process, they report again how much they expect to pay for those planned purchase items if they were to buy them later (we label this as POST). By randomly assigning participating consumers into different manipulated pricing conditions, the online experiment allows us to study how price changes inside the store affect the updating process of consumer price expectations and as a result how they impact purchase decisions.