For the Avon product there are a lot of fly recipes on the web. One is at section 2.3 of Fly Repellent for Horses

There are also other recipes using garlic (internal or external) and using essential oils.

Personally, I find that the results are fairly sort term (have to respray daily) with the homemade stuff. However, other people swear by them and say that it is as good as the commercial chemical products.

Please let us know how the Avon product works. If I hear a success story, perhaps I'll try again. Also, if you try the essential oils, I would be interested to know your experience with them.