Here is a list of products I use for my horses that are affordable and effective. ( I always encourage you to call the vet for life threatening situations with your horse).

These are products I always have on hand for emergencies:

Lameness

Recently my horse, Diva, was suffering from an abscess in her hoof. I used epsom slats to soak her hoof for 30 mins, twice daily and afterwards I packed her hoof with healing clay paste and wrapped it in a plastic bag with gorilla tape. She was better in two days! The salt and clay both draw out toxins. I love these products becasue they are natural, effective and cheap.

If you need warm or hot water for your horse, either to wash wounds or soak hooves, I use an outdoor water heater, Ecotemp L10. It's easy to hook up to a propane tank and hose. I use it for our outdoor bathtub and it works great. (Don't leave it out in freezing tempretures as pipes may burst).

Colic

A friend of mine introduced me to this product, Gas-X which works miracles on horses who are colicking. I have used Gas-X twice with instant results. I always have these on hand. I recommend the pepermint strips which dissolve immediately, just put under the horse's gums. They are more expensive than the soft gels which I recommend also, but becasue the peppermint strips dissolve instantly the horse has less chance of spitting them out. They stopped making the peppermint strips which is way they are double the price of the gel capsules but still well worth the investment to stop your horse colicking. 

Gas-X Thin Strip-Peppermint-18 ct.
Novartis Consumer Health Inc.