In line with the topic, I recently had a player tell me that they would only buy from me.
I actually suggested that it wasn't the greatest of ideas. Offers do come up that are better than my prices.
My advice, keep an eye out. It's really not so different as most things in game. Take advantage when you can.
As you stated in an earlier post (#8 in this thread) sometimes price is not the most important factor.
When I buy fragments I will often go with sellers I have dealt with in the past (Egami included - almost exclusively lol) who I have grown to trust and are easy to deal with. Of course, some times it's hard to pass up a great price and maybe get to know somebody new.
It's like picking between 2 hamburger joints next door to each other where 1 has slightly lower prices but rude and slow wait staff and there is essentially no difference in quality. Sometimes you may go with the cheaper one and deal with the staff but sometimes you may prefer to have the more pleasant dining experience for slightly more.
DISCLAIMERS:
* I'm not saying I have come across any rude frag farmers - it was just an analogy.
* I am also not trying to influence you to buy from any particular seller. There are many great sellers out there who I would love to see gain new business from this thread. I was just trying to explain why a buyer might decide to buy exclusively from a particular seller.