“Quickly indicate one's approval, say”

"Mine!"

Shoestring

It's over $30 trillion for the U.S., in brief

Place to end an engagement without breaking up

Some noblemen

Singer Rita whose last name is an anagram of 19-Across

Welcoming people to a party, say

Sporting blade that's an anagram of 16-Across

Retailer whose outdoor furniture items are named after Scandinavian islands