In a town the size of mine, there are quite a few vets versus the population size, & an even bigger disparity when you factor in the low-income families who just do
not take their pets to the vet at all, or very rarely. I totally "get" that the vets are trying hard to stay in business, & some mark-up is to be expected of course...but
when they had the nerve to tell me they didn't even have a prescription pad & could NOT write a prescription for my pet so I could fill it elsewhere with better prices,
& that they could only sell me the heartworm prevention medicine she needed, that's where I call "foul".
Not only did I find another vet after that, but I found one who told me about a very inexpensive OTC prevention medication for canine heartworms that I've used with
100% success for both my dogs ever since, at a tiny fraction of the cost of the various name brand products being sold. I use Ivermectin, as sold for cattle dosing in
local feedstores. The brand Ivomec has now given way to Noromectin, but it's identical, & available online from Jeffers at Jefferspet.com. A 50 ml. bottle will hold you
for several years, easily to expiration date & you'll have a lot left over, for a cost of roughly $30. (I donate 2/3 of my bottle to the local Humane Society shelter.) You'll
need an insulin syringe to dose* it very carefully though, I can't emphasize that enough, & they don't recommend using it for collies** & certain breeds** such as Italian
greyhounds+. This is given orally, monthly: I drip the dose onto a small bite of bread & dab a little peanut butter or something on top...my dogs love it, to say the least.
You would NOT want to add it to a bowl of food, in case they didn't finish it for some reason, or in case another pet gets into that bowl. Sorry, this may be a little off-
topic, but for anyone it helps, you're welcome.

(*
The exact dosage is 0.034 cc per 10 pounds of body weight, or approximately 0.1 cc per 30
pounds of body weight-) <This was taken from google search, there are various sources you can also verify showing similar info.
**
CAUTION: using Ivermectin, please read:
https://www.petmd.com/blogs/fullyvet...ermectin-29671
As I said, this may be a little off-topic, but my point is that some vets are there to help, more than for their own profits, but they're just harder to find it seems.