It's really hard to say without having all the details. When you say that 5k seems high for a dropped ceiling, is this because you've done one before in the same style that was less expensive? Or it's just not what you thought it would cost?

I'm always interested in people's reactions to estimates/pricing.

I would just ask as many questions as you can to clarify where the costs are going. And then you do have the right to shop around and compare pricing. Just be sure you are comparing apples to apples when doing so.

When I look at material pricing it seemed high. We asked for pretty generic stuff, so basic tiles cost (retail) less than $1 per sq ft. Grid about $1200 (again just basic retail searching).

We are usually DIY'ers but the entire basement was just too much for us to tackle. I'm willing to pay some for labor, but it just seemed high to me.

That's why I'm here asking, to see if that seems high.

I asked for a quote for our basement two years ago in MA, about 950 sq feet, with a bathroom, and I was told with the “winter discount” (slow season discount) 45K. This include some demolition,because it is already half finished.. I have not done it yet

It's hard to compare - because most DIY'ers are going to shop at big box stores and find cheap materials. While a contractor is most likely going to use a professional drop ceiling installer, and their recommended products. And most are going to mark up the material as well, as they are the ones handling and coordinating. Again, I can't comment whether or not it is 'high' as I do not know the specifics of what they are quoting. But I would assume that if you are trying to compare Home Depot pricing to a contractor bid, it will most likely seem high.