i think it's a very fair question. I also think that vets are OVERpaid, and ask a LOT because most people either need it or their animals will die, if it's bad enough, or pay it because they love their animals like children. It's truly unfair.
http://www.anapsid.org/resources/rxdose.html
You can see that a lot of the dewormers are dog dewormers or cat dewormers, that they sell at petsmart.
Most of this on the list you need a perscription for...however for instance i just went to the vet to get my dog's eye looked at, and recieved a perscription for liquid neomycin, which is an over the counter anti-bacterial. Oh, don't get me wrong, it also had an eye soother in it...the same ingredient as in Visine. Treated him for a simple case of conjunctivitus...pink eye...which i read later goes away on it's on. She was saying so many things and telling me how he could have an ulcer, and/or something behind his eyelid...talked faster than a used car salesman so of course i was like "save my dog!". I did fuss about cost and ask a lot of questions, not that it did me any good, though i felt like i was prepared to go in there...she was just a much faster talker than i expected. After my fussing she came back in and took a whole GRACIOUS 12 dollars off the 138 bill, because after all, she only WHIPED OUT one eye, not both!
I also didn't trust her information on my snake that i took in. Only a 42 exam fee there. She opened my snake's mouth, and listened for a heartbeat. THAT i an exam? Seriously.
I get so pissed off most of the time, but when i finally go in there i always feel swindled. I've treated two snakes from the pound, on my own, and have felt like i've done a hellava lot more good than if i had ever even brought them near a vet. They are thriving, and no vet fees. I've only been looking up each issue as it arises and have done just fine. Granted, obviously if i feel like its' over my head i'll take an animal in, but good lord...afterwards i just feel like an idiot.
Anyway, my point is, mr.spooky, it's a reasonable question by falconpunch, and there is not the simple answer of "oh if you want a pet, you should be prepared to take it to the vet and pay out the nose for any reason!!!"
It's perfectly fine to do home treatments for a lot of things. And successful. ANd yes, CHEAPER, but hey, you have to save money when you can for stupid things the vets want to charge.
I would make a terrible vet, considering i'd be more concerned with helping the animal, and making sure it's healthy than making double profit or more.
Another example...my dog needed some shots of adequan...$38 dollars a shot. Vet raised the price to $48 dollars a shot. I was able to find it from Drs Foster and Smith online (very reputable site) for $45 dollars a BOTTLE...which was almost FIVE shots each. ridiculous. When i asked the vet if he would match prices he flipped out and said no. Apparently it costs him more to order it...I do NOT see how considering the price i was able to order it for...with FREE shipping.
Greeeeeeedy.