I have Permethrin by the gallon, as I have horses, goats, and three dogs!! It does repel flies and ticks, as well as kills some other critters, but do not get it on your lips or tender skin. Avon's "Skin So Soft", has also been a wonder for folks who cannot tolerate DEET, or other nasty stuff. As you saw in the post by NTSQD, it comes in Picardin also!
Be sure to put the permethrin on before you go out, as since it is on your clothes that it repels and kills, you need it immeadiatly when leaving shelter. You can buy the permethrin spray at most feed stores, or animal supply places online like "Country Supply" and I imagine "Tractor Supply". The sprays are called fly sprays, and come in propelled, or pump spray. Just a note.....Permethrin WILL kill bees, and other beneficial insects, so do not spray on flowers or bushes.