EDIT: my apologies, I intended to make this reply to a different thread in this forum (LnBanD)
If money is a concern, given the season, you may consider making your own brew of Black-Walnut Hull Tincture - a great overall remedy especially for internally ridding various parasites.
If you live anywhere near public parks, take a few walks, find a walnut tree (walnuts are quite distinquishable by their rough/velvety green hull that give off a strong odor), collect a good-sized bag, go home and make your own tincture. All you need to do is soak the walnuts (entire - in the hull) for 3 days, covered in 100 proof vodka that itself is made from Grain Alcohol.... voila, you now have a large supply of your own internal bug killer, then discard the walnuts.