I have become quite the book collector since learning about homeopathy! And, I am a big fan of having reference books on hand to look up remedies for illness. You can always search 'cough + homeopathic remedy' on the internet, but the number of homeopathic reference sites online are dwindling and its just best to have a few books on hand.
Homeopathic Remedies: A Quick and Easy Guide to Common Disorders and Their Homeopathic Treatments by Asa Hershoff - This was my first book and is still my favorite, their are some wonderful illustrations and it is clear and easy to understand
Homeopathic Medicine for Children and Infants by Dana Ullman - This is my go to book for children! It is detailed and Dana Ullman is one of my favorite homeopathic authors
Everybody's Guide to Homeopathic Medicines by Stephen Cummings and Dana Ullman - I have heard good reviews on this one! It is a family book so if you dont want to get a separate one for infants, this might be a good compromise. If I buy another home reference book it will be this one.
Having a homeopathic kit on hand is helpful and more cost effective than buying remedies one by one, especially if you live in a rural area or don't have the ability to run to the store during an illness. Though it is an investment for many families, it is an important one to make. Kits can last for years and come out to PENNIES per dose. Add that to recovering from ailments quicker and a stronger immune system, and you not only have a lower cost overall, but a greater improvement to your health. I recommend having a 30 and 200 kit at home.
Helios Kit: via Amazon or straight from HeliosUK -- This was the first kit I bought, and has been a lifesaver! I travel with it anytime I go out of town. Helios also has a wonderful travel specific kit for traveling in less developed countries and a birth kit.
Washington Homeopathic Products: via Amazon or from Washington Homeopathics -- I love the products from WHP, I have the Top 100 Kit that I ended up loaning to a friend and currently have been carrying the Top 50 - 200c Kit.
I have added an affiliate link to my Amazon links to purchase books and kits, it wont cost you more but it gives a little bit back to me that I can use to keep running this site.