The explanatory variable is the price the subject expects to pay. The response variable is the price history observed.
This is a randomized comparative experiment because subjects were randomly assigned to treatments (price history).
This is an observational study because the researcher observes the price the subject expects to pay.
This is an experiment, but not randomized, because a treatment is imposed.
The explanatory variable is the price history observed. The response variable is the price the subject expects to pay.