Hammerhead said:
Somtimes. Other times there's no haggling, specifically one magical items merchant with whom most of the PCs intereracted. He had a sign that he would point to whenever some overly charismatic adventurer tried to get a better price. As a merchant, I'd implement a strict policy about such interactions and never deviate from it unless I was really confident about my negotiation skills.
True. Merchants will be in four categories:
1) Bad Hagglers. These will be anyone who's worse at haggling than the average person they deal with. For merchants of powerful magic items, they'll mostly be dealing with sorcerers, paladins, rogues, and bards--and for them to stay in business, they need to get the better end of the deal most of the time. The ones that don't do so, the bad hagglers, go out of business pretty quickly. This is therefore the rarest group; PCs who encounter one should rejoice at their good fortune

.
2) Good Hagglers. These are the ones who can, on average, out-haggle their primary clients (high-level PCs). They needn't fear some high-charisma schmoe with high diplomacy skills, because that's what these merchants are. They spend their whole lives haggling, and are only too delighted to haggle with some rube fresh from the dungeon who thinks a few ranks in diplomacy means they're the next Mr. Popeil. These guys are pretty common, and wise adventurers know that entering their shop is a gamble, and that odds always favor the house. However, shopping at a good haggler's store is always a delight: they may sit you down with a bottle of exquisite elven wine, fill you in on the city's best gossip, set you up for a night at their palatial estate, and get you invited to the Duke's masquerade ball, all in the process of fleecing you for every copper piece. Remember that these are merchants who cater to the VERY wealthy, and they want to keep you on their good side.
3) Tough-but-fair. These guys aren't good at haggling, but they know what things are worth. They stay in business by charging reasonable prices and by not being swayed by fancy words. PCs who don't want to gamble are advised to go here.
4) Tough-but-unfair. These guys think they're tough-but-fair, but they set prices poorly. If they set them too low, they go under quickly (see #1); if they set them too high, they also go under quickly (since nobody visits them). They're therefore the rarest of all groups.
A medium-sized town is lucky to have one magic-item vendor, who could fall into any of the four categories; a metropolis might have multiple representatives of each category.
Daniel