What's Cheap At Six Grand per Liter?

So, it seems that most dog owners dose their dogs with “spot-on” topical antiparasitics one a month to prevent fleas and ticks. It looks like I'll have to pick one for Scooter. There are a range of products to choose from, the popular brand names include Frontline, Advantage, and Advantix.

But, boy, are these things expensive!

Look at PetArmor, a generic for Frontline, and one of the cheapest options, in medium dog size. You get 3 doses; each dose is a tiny 1.34 ml plastic pipette, and the cost at Walmart is $25. That's $25 for about 4ml, or $6,250 per liter. OK, so maybe working out a cost per liter is not entirely fair, since it comes in three tiny plastic vials, but if you can get 1ml glass vials for $100/1000, or 10¢ each, online, these little plastic ones can't be all that expensive, so the ingredients must be super-expensive or something, right?

Mmmm… no. The basic Frontline (or PetArmor of Fiproguard) is a 9.8% solution of fipronil in, presumably, some kind of oil (fipronil is only very slightly soluble in water and the mechanism of action suggests a chemically inert edible oil, probably some kind of mineral oil like the stuff you buy in Ikea to rub into your wooden chopping boards at $10/liter or 1¢/ml). Fipronil itself can't be all that expensive, since you can get it in a 9.1% suspension (in water) for about $100/liter for termite control (Termidor SC or Taurus SC). Even if the entire cost of these products was solely in the fipronil, each vial would contain about 15¢ worth. So the material cost for 3 vials of these topical antiparasitics, including packaging, can't reasonably exceed $1, so why does it cost 25 to 60 times that? Inquiring minds want to know.