Letters in one piece
I write a lot of letters. A lot. You do not want to know what my monthly postage bill is, believe me. But I have never written a letterfu letter, although that is about to change. Letterfu is a folding technique that lets you write your letter on a single piece of paper, fold it up, seal it with just the postage stamp, and post it. You can print out pre-made designs, or, if you've got some mad photoshop skillz, make your own. In fact, if someone wanted to make a Style Graduate letterfu design, that would be awesome, and we'd feature you in a future post! As long as you keep the fold lines where they should be, you're set. I recommend a heavier paperstock than normal.
Much more on envelope and letter folding can be found here.