1) An Album - Select the size album you want to work in and find a color or pattern that works for the theme of your album.
2) Refill pages for your album. Refills are not standard sizes, so it is best to pick up a few packs when you purchase your album so that you get the same manufacturer and size. This way you will not have to hunt for the refills later.
3) A nice sharp pair of scissors. My favorites have very fine tips and are comfortable to hold in my hand. You want a pair of scissors that are dedicated exclusively to your scrapbooking. This way they are always with your supplies and always nice and sharp.
4) Adhesive. There are many, many different styles of adhesive. To get started you want an acid-free adhesive that will work well on both cardstock and photos. A couple of my personal favorites are: 3L Click 'n' Stick Mounting Squares, Herma Dotto Removable, and Herma Vario Wheel Dispenser. To see a complete collection of the different types of adhesive available and tips for their use visit the Scrapbook Adhesive gallery.
5) Cardstock and Patterned Papers. Select paper to go with the colors you wish to accent in your photos. You may want to purchase paper at your local scrapbook store so that you can select individual sheets for each page.
6) Journal Pens. Look for acid-free, permanant, pens with fine tips for hand writing your journaling. If you wish to hand write titles for your pages you may wish to purchase pens that have a fine tip on one end and a wider tip on the opposite end. Read Handwriting on Your Scrapbook Pages to help you get started using journaling pens.
Those are the essentials, but as with any craft, there is always more that you may want to add to your supplies. Here are the ones that I would add next.
Very High on the "Want" List:
1) A 12" Paper Trimmer.
2) Embellishments that coordinate with your pages, such as stickers, 3-D Stickers, buttons, and more. You will also want to learn simple new scrapbooking techniques that allow you create your own page embellishments.
3) Ideas to Inspire You. Layout galleries and free scrapbook page sketches will help you get started creating beautiful scrapbook pages.
Additional Items to Consider When Budget Allows:
1) A Die Cut Machine with an Alphabet Set of Dies.
2) Full Set of Journaling Pens.
3) Circle/Oval Cutter.
4) More, more, more. Once you get started it's hard to stop. You will find yourself wanting more paper, more embellishments, and eventually more albums!