A lot of times cities have a class that they recommend or offer when they test. Ask the inspector. If it's an NEC test, look up Tom Henry's courses. They were geared for the Florida test, so I don't know how helpful it will be Philly but he has books with old test questions and answers. Check the books out. If they seem similar to the test questions, check out where he has his classes. I know he located around the country.
I would never have passed the Florida test without the class. Not only do you learn what you need to know to pass the test, you learn things that will assist you throughout your career. Well worth it.