You don't need programming skills to be a successful affiliate, but it certainly can help. Programming can not only help your affiliate projects, but broaden your skill-set to expand your business.

Here are some resources to help you get started programming. There are thousands to choose from, but these are a good start. I'm not an expert programmer myself by any means, so I refer to these resources often. From an affiliate perspective (and arguably overall) the best language to learn would be PHP.

Free Resources

Code Year
Code Academy
Massive List of Free Resources
W3 Schools
Google Developers

Paid Options

Code School
Tree House
Udemy

You'll need a basic HTML editor

Kompozer  – Free
Coffee Cup – Free
DreamWeaver – Paid

Depending on what you're doing, you may need an editor like

Bluefish
Notepad++

For motivation, here are a few good reads

It's not too late to learn how to code
6th Grade Developer
How I made $19,000 on the app store while learning to code

Even if you don't want to be a developer, it will help any type of online business you do to have a basic concept of coding. Even if you outsource your coding, learning about it will help you know if an outsourced programmer is doing a good job and charging a fair price.