Why don’t you go for a Guiness World Record? (The answer is that I applied for the World Record as Richest Player in World of Warcraft in November 2015 but they “do not invite proactive applications for records such as the one you are proposing” and suggested I go for “world’s longest Warcraft livestream” instead. Zzzzz no skill needed, no thank you!)
That being said, there are occasions when a little kindness is not unwarranted. A typical example is a new player who just dinged level 20. They are suddenly confronted with a whole set of relatively expensive skills at his or her class trainer, and the cost of mount and riding training, and needs a small amount of money to learn those new skills. Likewise, sometimes one sees a player who, just by the way he or she walks, is clearly a new player. Kindness to non-whiny, well-intentioned, legitimately inquisitive newbies is karmically rewarding, and one should not worry about shelling out an occasional boon to such players. Remember, at that level, a few gold can go a long way. Heck, even a few older bags that you have lying around collecting dust in your vault will often be much appreciated.
2. Once you have an interested buyer, stay firm in your price. This does not mean to never make them feel like they are getting a bargain. You can subtract 5% off the price and not be hurt as long as you still make a profit! Remember this, as that 5% may not be a big deal to you, but the buyer will feel special and might buy the item for the slightly reduced price. I can not emphasize enough that this is not the same as undercutting! Do not drop every good every time or you develop a reputation as a soft seller and people take more liberties in their dealings with you. If you give someone a constant 5% discount, then they begin to want 10% and then 15% until you no longer make a profit. Discounts are used when you feel that the seller may be pulling away and you really want to just profit and move on!