You do not need a computer to begin affiliate marketing. You can start with just a smartphone. Many affiliate programs allow you to sign up and promote products from your phone. You will need access to the internet to find affiliate programs. You can also use social media apps to share affiliate links. You can track your sales and commissions through mobile apps. However a computer can make things easier. It allows you to work on a bigger screen and manage multiple tasks. If you have a computer it will help you work more efficiently but it is not a must.