My collie/lab developed a very inflamed right eye and I decided to treat it myself with some Gentamycin drops I had bought for my sore eye whiie in Spain (fine dust, methinks).
If drops are properly applied, they should not touch the eye at all, and while I know there are many out there who maintain dogs should not have human medication, I bathed her eyes eye with normal saline and used the drops: the inflammation cleared in 24 hours.
I was the one who was stinging, having been charged £50 for a Viacutan pump spray some weeks earlier - it's available online for less than £19.
While I appreciate that vets have costs and overheads, I cannot see how they can justify charging such a price.
However, I would never give my dog ANY internal human medication.