The only problem to lowering a price as a result of haggling for me, is that the buyer then expects to get the premium full price service. I did this once and never again. He was a handful to deal with, didn't have a clue about anything so it made it even more hard work as I had to think for him and his business (not really my job) and he was expecting to get extras thrown in that are not even thrown in for any full-paying customer, let alone someone who beat you down!Had it been a breeze then I might have felt it was worth doing.
Personally I find it rude in a professional setting to haggle down a professional service and even then, I wouldn't try and haggle down a plumber or builder. To me, their first price should be their best price. But i'd also be savvy enough to know that if I ask for it cheaply, I may not gain any loyalty from them.They will hardly want me as a customer in the future. There are folk that haggle even when they do not realise the cost they are given is actually, a good price already! They also are not savvy enough to work out that within any sale there is the hidden support/customer service that is included in the price quoted. You're paying for quality, guarantees, support of a better/higher level, etc.
Good business relationships work 2 ways. My customers who pay the full price, and on time, don't try and get stuff for nowt, and they actually earn invisible credits from me for their loyalty.
I do odd things here and there for free or I give them lots of free advice/consultancy when there is otherwise nothing in it for me to do so - stuff that is normally chargeable.
My longest serving client deleted her ecommerce admin files in the hosting control panel in blissful error - I had her site back up and live, restored from a backup I happened to have, and at no charge, despite a churn of back and forth emails also taking up my time, until I realised what she had done.
The only time haggling should be done is if you are asking for a lot of something. If someone comes to me for 2 or more websites I am going to discount if ordered at the same time.....And not on that old chestnut "I could bring lots of work your way if the price is right". Or the 'we are a charity" and I say, well when your CEO drops his pay from £48,000 PA to £46,000 I may consider it!
After all, what you are in fact asking is if the seller will take home less pay, so the seller has to do the maths and still make it viable to be worth taking on and in order to do say, may not be able to offer you the hidden benefits/brownie points you may otherwise have got. Just something to consider when haggling down. I think it all depends on what, when and where, as well as what you actually expect in return for your money.