Not considering salary how badly do you want to work for this company and anticipate the salary might become higher in the future? If you honestly need time to decide that you are willing to accept the lower wage then ask them for a couple of days maximum to get back to them. What is best is during the interview to do your best to negotiate and try to see whether a higher salary is even a possibility. Remember right now it is to the employers advantage as there are more people looking than there are companies hiring.

If AN interviewer aggressivly offerS a LOW SALARY and is not willing to negotiate because they are A top company or my dream company, could I say "could I get back to you this week?" How many days OF DELAY is acceptable? Or is IT better to responD yes or no right away? Waiting to repond is normal but it also risks that they give the job to someone else. I suggest you be be prepared to answer if possible.