"Congratulations, we would like to offer you the job. What is the lowest amount we can pay you for you to be happy here?"
That isn't what the Recruiter will say, but it's what they really mean. Accepting a new job is when you will get the biggest pay raise. A good company will want to pay you a fair salary but not over-pay you. So, how do you ensure you get the best offer?
Research
First of all, before you have your first interview do some preparation. What is the lowest amount you can afford to take? Then do some research online to find out what people in these positions with the same amount of experience as you, in the same size company are being paid in your area. These are all factors that will determine your market value. If you have people in your network that work for the company or similar companies see if they can give you ideas on salary for that position too. Based on all this information, come up with a ballpark number that you would be happy working for.
Justification
Next, write down why you deserve that amount. How much money have you saved your previous company? What have you earned before? What have people in similar positions earned before? What unique value can you bring to the company?
Range
There is a rule in sales that the first person to bring up a number loses. Wait until the Recruiter or hiring manager brings up the subject of salary before mentioning it at all. When they do ask, respond by asking what the salary range is for the position. It is very unusual for a skilled position to have a fixed rate of pay. Companies typically have a minimum and maximum salary for each position. If your number is within the range, then tell them (or something a tiny bit higher so you have some wiggle room.)
Decision
If your number is higher than their maximum number you have a decision to make. How much do you want the job? Should you walk away from this position and wait for the next suitable one? Are you prepared to lower your number because its a company you really want to work for or the position would be a great jumping point to another position? Do you want to accept a lower number but ask for more non-salary items like more paid time off, having professional membership subscriptions paid or having them pay for a certification for you. All these options are viable.
Agree
As you negotiate be pleasant, positive and open-minded. Remember this is a business transaction and keep emotions out of it. Focus on making it a win-win. And lastly, and most importantly, whatever you decide and agree upon - get it in writing!
A career coach can help you with salary negotiation, and the additional salary they will help you get will often pay for all your coaching.
You might also be interested in reading: How to decline a job offer.