To get you off and knitting, you will need 2 pairs of the correct size needles, a ball of machine-washable wool, measuring tape, and a small pair of scissors. You will also need a tapestry or yarn needle. These are large blunt-ended needles with a large eye used for stitching the back seam and finishing off the bottom edge. Knitting worsted wool is a good choice,
Michaels Craft stores and some dollar stores have everything you need to get started, and they usually have a good selection of colours at competitive prices.
If you are new to knitting, then start by using a single colour. Stripes are an easy jump from there, and when you are feeling a little more creative, start to use some of the patterns.
Get started with Knitting Worsted Wool.