Well, I am certainly not advising that anyone should try to make either AuCl3 or AgNO3. Quickly looking at the costs of the materials needed for making AgNO3, unless you had the silver and Nitric Acid on hand, there wouldn't be any savings. Even so, making AgNO3 appears to be a "dissolve the silver and let the result evaporate process" and you have your material. This AuCl3 refining process is a whole magnitute of disaster above that.

Buy the stuff. Mix up developers or emulsions if you want to play chemist. Metals refining is a mess.