Final answer:
The vital step during the preparation of a market rental survey is to collect data on prices by visiting or calling stores and conducting a survey of landlords or tenants.
Step-by-step explanation:
The vital step during the preparation of a market rental survey is to collect data on prices. This involves visiting or calling stores in different urban areas to collect prices on specific products. In addition, conducting a survey of landlords or tenants is necessary to gather information about rents.