I dont haggle either. If I think the price is too high I dont buy the goods.
I was in a charity shop and a coat was marked up at a tenner, it was a good coat with a brand name, the customer tried to get a fiver off. I found it distasteful.
I have also done car boots, my clothes, I was told by many customer's were reasonably priced, clean, and good quality. I wanted am £4 for one thing and I had someone offer me £2. I told them politely I was not shifting on price. Someone half an hour later paid the full price and got a real bargain.
My advice is pay the full price.