Why did matthew perry include a second letter in the gift to japanese leaders? ?

Most likely the United States House of Representatives had not approved a single cent with which to pay for it.

"Alaska is nothing but a wasteland of glaciers and polar bears" is wrong 100% 
The U.S. agreed to purchase Alaska from the Russians for $7.2 million, only 2.5 cents an acre, though Congress had yet to approve a single cent for the deal. Few Americans, viewed Alaska as a bargain. The press mocked the purchase as "Seward's Folly," and "Seward's Icebox." But nearly one year later, and after much political wrangling, the U.S. Treasury finally wrote the check. And Alaska became a U.S. territory.