Sheath cleaning you could definitely learn how to do yourself.
I've done my own shots for years, because of the ridiculous charges to have a vet to it. Rabies is the only one you can't do without a vet; you 'normally' can not even purchase it, unless you're in a state that doesn't require a vet certificate to verify the horse actually has had it; your own records won't suffice there.
As far as the charges you've gotten, it does sound about 'right' for all the work you had done; ridiculous yes, but 'normal'.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."