how do you find out about local casting calls?

Answer 1

Buy a tractor Pull magazine. It has tons of parts in it.

Answer 2

Where is "Local"? If it is one of the major cities such as New York or Los Angeles then you can read the trade papers like "Back Stage". Some people go on line and read "Craig's List" others subscribe to the "Breakdown Service".
I would look in the telephone book for the telephone numbers of all of the theaters that I would be interested in performing and I would call them and ask them about their casting information. I would also check the bulletin boards of the drama departments at local colleges and universities for their casting notices.
Networking is another way to get information on casting; do you attend any classes or workshops? Ask the other thespians around you. Break a leg!

Answer 3

Every large city in the USA has newspapers dedicated to auditions.

Go to the largest newstand in the city where you live and ask the store clerk for the newspaper that actors purchase.

Answer 4

the local ones are scams. You need to get better connections to whatever industry you want. Consider moving to the area that interests you, instead of expecting one of their agents to come to you. You will pay a heavy price if you let them come to you.