I can't speak for Rome because I have not been in churches there but for the rest of Italy, 99% of churches are Free Entry and the few very famous touristic attractions have a single fee no matter who you are.

Maybe you are confusing paying for a guide as tourist with paying to visit the church.

Free entry - but for those going for the religious service. That's not me. At least that's how it was all around northern Italy few years ago when I visited.