http://www.theweedblog.com/how-to-make-your-own-marijuana-fertilizers/
"One of the strangest fertilizers you may have ever heard of is human urine. Indeed, the yellow stuff is chalk full of the nitrogen that can promote stem and leaf production. It is important to not urinate directly on the marijuana plants or even near the plants because it might kill where it touches."
If you took chemistry you understand that fertilizers are nothing but elemental salts. The N in piss is the same N in the air and the water etc. How much you want to pay for someone to mix and bottle it is up to you. Cheap GH Flora series nutes produce great results - in the right hands.