About five or six years back, I went as an Ape from the original Planet of the Apes (you know, the one with Heston). I bought a latex appliance from www.ScreamTeam.com. I liked the outcome of the costume, so I decided to use their "Beast" appliance to make me look more Teen Wolfish.
This one didn't come out too bad, so I thought I'd post the process here.
Step 1: Jacket
I luckily found a letter jacket on eBay for $20 that was about my size. It was a pretty close match to the one Fox wore in the movie.
I ordered a 7 inch Chenille Letter "B" in royal blue on black felt on light gold felt. I don't remember where I got it, but you can google chenille letter for lots of options. Expect to pay around $20.
I used 3m Super 77 spray adhesive and sprayed the back of the letter. I then attached it to the jacket. I did this primarily to hold it in place while I ran it through my wife's sewing machine to keep the letter from coming off.