I didn't even know there was one...?
Probably why it's called the rare Let Go sketchbook ;)

Q: What's the 'rare Let Go sketchbook'?

A: There's not much difference between the sketchbook & the regular album itself. You get a Matrix remix of 'Complicated' but that's it. The rest of the sketchbook features a 4-page biography of Avril [because it's her debut album], some drawings that Avril drew, some photos of Avril herself & of course, the Let Go album lyrics. This is all bound together in a sketchbook, which is appropriately, why is it called the Let Go sketchbook. Yes, it's rare, I haven't seen that many of them [only 3 to be exact]- I think they only made 100 of them but I'm not totally sure. So that's why I bought it when I had the chance.
I bought it on ebay for around $50- because I like buying rare musician items. Who knows? Maybe you'll be the next one owning this awesome piece of Avril Lavigne memorabilia. ;P

Wow awesome, back in 2002 I didn't even know who she was (shameful, I hate admitting that). But it's awesome that you have one when they only released a few copies :) I just have the normal Let Go album ;)