Besides PSA's and PI's, another way a new station gets started is by trade-outs ... but you can't live on trade-outs alone. For example:
Way back in '68, being young and naive, I had the chance to move up to a Director position by helping start a new station in Ft. Lauderdale - WSMS/TV51. We had a couple of TK-42's two VTR's and one (count 'em) ONE film chain (with most evening shows and spots (PSA's) on film). The place used to be an old furniture store with a small storeroom in the back that was our studio.
And there was a reason we had sets on hinges that could easily fold out into other sets; we would sign on in the afternoon with Romper Room (live), then an old film while we set up for an afternoon talk show (live), then cartoons while we set up for another kids show (live), then another film while we set up for news (live). The schedule changed for a couple of months, resulting in back-to-back live programs. It was a challenge, and it was fun.
There was this one spot for a nightclub that ran almost every other break. They seemed to be the only business in town that was really supporting us, and I made a comment to one of the engineers about it. He burst out laughing.
"Supporting us? Ha Ha ... Man, they're a trade out. Where do you think the guys in the front spend most of their time when they leave here? We're just payin' their tab, and I hope you have your resume up to date."
A few months later, I accepted another job with another station (established network affiliate) in another city, and WSMS lasted about a year.
I hated leaving Ft. Lauderdale, that station, the beaches, and especially my apartment that was located across the street from the girl's dorm of a finishing school. I never needed no stinkin' night club for trade outs ... BUT, that's another story for another thread. ;D