Select a palette of colors you'll use. This will vary depending on what you'll be painting - a landscape, a figure/portrait and so on.
Include on your list a good range for a beginner: cadmium yellow medium, cerulean blue, ultramarine blue, alizarin crimson, cadmium red medium, burnt umber, lamp black and white.
Decide which of the two different types of oil paint you'll get: ones made with pure pigment and binder or ones made with artificial pigment and binder. Artificial paints are good for beginning painters and for people who don't need to have their work last permanently.
Select pure pigment paints for college-level artwork and professional fine art. These paints will hold their colors when mixed with other colors and don't fade.
Buy oil paints online or at art and craft stores. Look for the pure colors behind the counter or locked behind glass.
Purchase turpentine to clean your brushes and thin your paint.