"To push it becomes extremely embarrassing to the person on the other side. You can make them feel so uncomfortable."
The internet has become a great tool for comparing prices and asking retailers to match or beat their rivals, but smaller shops often pay more for their wholesale goods than the giant chains do.
"A smaller retailer might not have the margin that they can discount like a big retailer can.
Not everything can be discounted at the same rate at different places," Zimmerman says.
Lying about competitors' prices won't work.
"Retailers will make the call to a department store, or check online, to confirm. Don't try to take them for fools."
Buyologists founder Mike Chalmers says you should avoid signalling that you are happy with the ticketed price or are desperate to buy now.
"Always do your homework first so you know exactly who is offering what where, and search online for any coupons or special offers that you might be able to use," he says.
Saying nothing can be a great negotiation tactic. "Silence is your friend - if they are thinking about what they can do, don't say anything to fill the gap, just let them respond," Chalmers says.
Keep your emotions under control. Always avoid anger, and never act too excited about a product, he says.
"Take emotion out of it and show them you are prepared to walk away if they won't give you the right price."
