I may be wrong but I've seen a lot of people use mouthwash. Just dilute it with water. Cheap and effective. I can vouch personally that it works very well. During a horsecamp where that was ALL they used, we all went around smelling a bit like mouthwash because we would douse ourselves in it before we went riding. I think I got one bug bite on my ankle during the combined horsecamps I KNOW they used it (two horsecamps). That was also the day I decided NOT to spray my pants with the stuff for humans and the day someone else sprayed my horse for me.