Is the Power Steering pump supposed to whine?

What is your question?

I test drove a 2007 Dodge Grand Caravan today that I will buy - or not - tomorrow. During the test drive we got onto the highway. When we exited and pulled into a gas station I turned off the air to listen more closely to everything. A hum / whine sound gets louder as the vehicle slows down and continues while stopped. My husband can mimic the note perfectly. It seems to be on the left side of the engine (looking into the engine) but is louder inside the cabin! The seller told me that’s the sound all mini-vans make and that it’s the power steering pump. In other words “normal”. It changes a bit when the wheels are turned to the left and right, which indicates it’s the power steering pump. We checked the fluid and it was full and did not appear to be leaking. Do mini-vans make this sound normally?? If not, is the power steering pump going out? How much to repair?

What makes this problem better or worse?

Nothing. It’s constant.