How much is a one week vacation from the USA to Amsterdam?

Vacations don't have a single cost. There are huge variables, depending on when you go, how you travel, where you stay, what you do, and exactly where you're going from. 

I was already living in Europe when I went to Amsterdam.  I got a student pass and it cost 26 pound sterling.  Hotels were cheap, hash was cheaper than in UK.  It wasn't an expensive holiday at all.

Try asking in 6 months. 

That depends on when you go, where you stay and what you see/do/eat while you're there. I usually count on around $150 per night for a hotel. The cost of the flight will depend on where you fly from as well as when. Check airfares for when you want to go on sites like Kayak. Then I usually spend $75 to $100 per day there.

Impossible to answer not enough detail.

It would depend on when you flew which airline you flew with.

What star hotel you stay at.

Also with the Corona Virus crisis at the moment.

You wouldn't be aloud to enter the Netherlands from the USA for a vacation

what do you mean?