There's a story I read online a few years back - presumably on a screenwriter's or producer's blog IF YOU KNOW WHERE IT IS SO I CAN LINK TO IT, PLEASE POINT ME TO IT? - The story is roughly along the lines of a cautionary tale:
Basically, a producer [I'm going to say HE, but it could just as easily be SHE] was asked how he dealt with a writer (specifically writers new to the business?) who asked for more money, perks, etc than he wanted to give them. The producer responded, that's easy, I hang up noisily, then ring them back and apologise for the unexpected hang up, tell them I dropped the phone, and then instantly launch in to: well that figure that we agreed of X (X being LOWER/WORSE than the amount the writer was talking about) ... and bulldozes through the rest of the conversation from there. Summing up his anecdote with: This tactic is great! It works every time!
For any writer who encounters this, I would suggest that the correct response is to either tell them what for, or if you are in too much shock to know how to respond, just hang up on the Producer.
I know you don't want to, he believes in you, he's talking about making your film!
But hang up on him anyway. And then go for a walk, while you figure out how you feel about this champion who turned out to be more concerned about his own cut than your welfare: your ability to pay for essentials like food and rent, your career. ... He's "A PRODUCER", why are you surprised? - - It's not nice behaviour, it's certainly not professional behaviour on their part, but it happens.
And in a business that is built on trust, it is a BAD IDEA.
He/she will ring back. (Probably.)
Your screenplay attracted them enough that they want to nail you to a deal - - from your point of view a crappy deal. They will ring back. And you need to be prepared to handle them when they do ... or get an intermediary to do it for you. (It's only one of the many reasons why the elusive AGENT, or ENTERTAINMENT ATTORNEY/SOLICITOR is a sought after commodity)
Any producers reading this who think, "Hey, that's a good wheeze! I'll try it!" I would recommend that you don't. YOU WILL LOSE THE WRITER'S TRUST (also their goodwill). YOU WILL BE STABBING YOURSELF IN THE FOOT! As suggested above: The film industry is one that is built on trust, why throw your reputation away for short term greed?
Especially if you are planning a three picture deal with that writer. ... Pure lunacy.
I know this actually happens. It happened to me, once upon a time.
If someone tries to feed you crap, and tells you bullshit is edible, you have to be prepared to walk away.
There are other producers out there.
You're a writer. You have stories. A producer needs stories in order to stay in business. If you behave nicely and play well, then you will always have the upper hand - no matter how much of a social or emotional cripple you are! THEY NEED YOU.
There are more producers swimming in the pond.
Go "Wave your wooden leg!"
Right, you've been warned. I'm off back to the cave to write. :)