Last week, we looked at The Achievement Junky and discussed the importance of maintaining listings that appeal to this type of buyer. This week, we look at The Collector. As with all posts, YMMV.
The Collector is most likely an Achievement Junky, however that is not always the case. Regardless, The Collector is trying to get as many of one type of thing as possible. Most of the time, this coincides with an achievement, such as is the case with pets and mounts, or it might be that The Collector is trying to complete an armor set in preparation for Transmogrification in 4.3. Or, it may be that the player simply wants to have every pattern or recipe for their profession. Generally speaking, The Collector has a list of what he or she needs and they shop the AH to see what they can find prior to going out and finding the items in-game.
To sell to The Collector, simply acquire collectible items and make them available on the AH. The most obvious example is with pets. Outside of Stormwind is a lady in a house who sells four or five different types of cats. Each one of these cats sells for a handful of silver. These can be listed for a huge markup and people buy them like crazy. On our server, they will sell for up to 10g each.