Now that you have these addons, it is time to set them up properly to be used as effectively as possible. With the first addon listed, Auctionator, you will get three additional tabs when you open up the auction house: buy, sell, and more. Buy and sell are easy to follow and read, the primary reason why this addon is the top choice and listed as number 1. You can easily set how much to buy or sell, ranging from 1 individual object to stacks of the same good. The most important way to search is by price per individual item. This will avoid both overpaying and underselling, since you can see what one item in a stack is worth compared to what it is worth when being sold on its own. The "more" feature provides an easy-to-follow window of all your auctions up and the details associated with your auction, such as price and time left, in a nice color coded fashion. Without this addon, you will be severely crippled compared to anyone using this efficiently. If you are afraid of addons for security reasons, the rest can be ignored as long as you have Auctionator!
4. Is there a guild waiting for you on the target server that you are satisfied with? Often times, I have transferred to a server, made a lot of gold and quit the game out of boredom because I was without a guild. Another aspect behind this question is that often times in guilds, you can get free flasks and materials to craft goods instead of spending your own gold. This will add up in the long run, whether it's free repairs or free abyss crystals. Remember, you can always send the crystals to another toon and sell them for gold as well.
The neutral auction house can become one of your best friends. Other players are constantly checking both factions' auction houses to find an appropriate price for the good they demand. Often times, goods are cheaper on the alliance because they have more people, thus, the supply increases as demand decreases and price goes down. If you are horde, feel free to transfer gold to your alliance toon through the neutral auction house in order to buy them item and bring it back to the horde side where it is more expensive. The 15%, as of patch 3.3.3 (down from 30%) is well worth the extra 50% or more you can easily make on one item alone. Blizzard decreased the neutral cut for a reason to 15%, that reason is to get trade facilitated between the horde and alliance. Make sure you take advantage of this! Tips when trading between factions:

Although the Battle Pet Trainer will only offer to teach you your race-specific companion, it is possible to add all of these pets to your collection. You can either find them in your faction’s auction house or you can create a character of the race whose pet you would like to learn. Using your new character, you can seek out any battle pet trainer in major cities. After you learn the pet, you can delete the character; the pet you learned will not be removed from your collection.

×