What is the easiest and most inexpensive way to bind some pages to make a nice book for a gift?

I have probably about hundred or more pages that I printed out on regular 8.5x11 paper. I want to bind them together to make a nice book for my sister for Christmas. I am not too crafty, but I can follow instructions if anyone can direct me to a web link or could just type up their own instructions that would be greatly appreciated. And don't worry I left space on the margins for when I bind it.