100% would only give me a discounted price if I paid cash, or it was +3%. If I'd been paying the ticket price, different story.
I have the complete opposite experience and I buy quite a few gadgets.
eg, most recently , I recently negotiated to buy a Nikon D600 with lens from HN for $3500 - at the time, this was the cheapest price from an official supplier by around $400. Then, paid by CC. Before then, I negotiated a great discount off a Samsung 40" led tv from JB Hifi, paid by CC no worries.
The best place to buy is Noel Leeming - -you can get the discount (usually I'd expect 20% minimum otherwise I walk), the credit card reward points, and flybuys.