In high-haggling countries, you almost always do better by having the exact amount of money you want to pay in your hand.
Vendors, merchants, and hawkers are torn between wanting to make a sale and profit, and wanting to hold out to get a higher amount.
But something about physically handing them notes or coins when making your offer makes it much more compelling.
When you say "50 dollars" as a bid on an item, it's easier to reject that in the abstract to hold out for more. But, "Here's a 50... it's all I've got... can I take the item?" -- this has a much, much higher success rate.