The situation is also an important part of haggling. If I'm out on the first day of a 2 day reptile show and shopping for something specific then I don't expect much wiggle room on a price. Usually I go on the second day. I found a Spider Mojave that was very nice looking but had a wobble. All the other ones at the show were 400-600$ and this one was priced at 200$. I knew the vendor really wanted to sell it so I offered him 150$ and he accepted. Now I have a beautiful snake at a great price that is growing like a weed.
When there is a snake you really want, and you have an amount you want to pay. You tell him he can sell you the snake for the price you've asked, or he can take the snake home, make no money, and continue to pay to feed it. It's makes the seller believe it's in his best interest to sell to you. That's how I haggle.