like missi said, you definitely don't have to print them out right now or even at all! i have hundreds of scraps and have only printed maybe 10 ever. i just don't have the money to do it right now, but they're saved for when i can in the future and put together a book.
don't let that thought hold you back, with all the welcome wagon goodies and the cool stuff terra gives out at the friday night scrpas AND the blog daily downloads and everything, you can probably scrap forever without spending a dime! ;)
hope to see you at the scrap tonight!