I agree with glad. I got a good deal from this guy at HN central but when the other forumers tried, they don't seem to be able to get as good a deal from him.
But it's good for us to share and for the others on this thread to have a few more options for comparisons. Saves a lot of time on searching. What I did was to decide on the models of the items I want, I call up those that can offer a good deal and head down when i find one.
Recently, I was looking for SLR cameras and managed to find this guy at HN novena who offered me a great deal. Though this thread is about appliances and not cameras, the guy said he can give good deals for appliances should any forumers need his contact number to try their luck, just let me know, I'll be glad to share his contact.
I've not encountered admin charges on my purchases with HN using CC, though there would be a difference in pricing using cash and card. They'll normally be able to lower the price by maybe about $20(eg for item that cost about $1K) if you are paying cash upfront. But ultimately, it's up to individual to choose to pay by instalments or hard cash. All of us just want to get as good a bargain as we can that's all.