A trade-last is an old expression for a compliment that a person has heard and offers to repeat to the one complimented in exchange for a compliment made about oneself. This phrase is recorded in the Dictionary of American Regional English through the U.S., but the variant "last-go-trade" is also found in the middle and south Atlantic states, and at least once a phonetic rendering of this, "Alaskan trade" has made it into print.
An example of the phrase's use, quoted in the A.Word.A.Day e-mail newsletter:
"'I have a trade-last for you, Ida,' she said. 'Mrs. Mallard is in
the library, discussing our club, and I heard mother say something awfully nice about you.'
'Tell it!' demanded Lloyd.
'No, I said a trade-last.'
'Oh, fishing for a compliment!' sang Katie."
(Annie Fellows Johnston (1863-1931); The Little Colonel at Boarding-School, 1903)
"Trade-last" also is the name of a type of pink daylily with a greenish-yellow center, a hybrid between the Fairy Tale Pink and Southern Charmer varieties.
Sources:
http://www.wordsmith.org/words/trade-last.html
http://www.wordsmith.org/awad/awadmail94.html
http://www.littlecolonel.com/Books/BoardingSchool/Chapter05.htm
http://www.neh.gov/news/humanities/2004-03/lexicographers.html
http://www.cr.nps.gov/history/online_books/regional_review/vol4-2g.htm
http://www.hyperdictionary.com/dictionary/trade-last
http://www.bartleby.com/61/41/T0304100.html
http://www.floralacres.com/asp/display.asp?Name=Trade-Last
http://plantsdatabase.com/showpicture/6494/
http://home.att.net/~moregarden/gracedaylily/grace.htm