Depending on where you are, they should be smaller community theaters that really depend on developing new local talent, as it helps them keep their costs down. If you can afford no/low pay, this is a great way to get experience. It's like working on a B-move to hone your craft before trying for big budget jobs.
Just call up or go to every theatre within driving distance. If you know of a larger house of worship, they usually are looking for people too. Also any regional theaters, road/touring houses, universities or colleges in the area? At smaller campuses with a theatre dept. they need overhire work often. Even at big campuses, there is occasional need for loading crews.
There usually something available all the time if you look and ask around. The best way to get experience is to do the low/no pay jobs for a little bit then use your resume and references along the way to go out for the bigger stuff. You'll feel more comfortable about interviewing too.