Quote Originally Posted by birdgirl73
I know the OTC stuff modeled after revolution from the pet stores doesn't have the same level of ingredients that the Rx stuff does from the vet and is less effective. But it's definitely cheaper. (Revolution is pricey as heck.)

As far as how much stock to put in a OTC product you get at the pet store, you could call the SPCA, a shelter, or even a vet's office and explain your moneyless state and ask them some questions about whether that stuff they sell in the pet stores is even worth buying. They have vet techs on staff at those places who know these answers and would also know how to tell you to treat the dog's skin condition with that medicine you already bought. If you're persuasive and persistent and ask in the right way, I expect those folks would be glad to help provide educated answers.
I know "Heartz" brand can actually be deadly...