Aeria Points (commonly known shorthand as AP) are usually earned by purchasing straight from the cash shop. But Aeria Points can also be earned free from completing partner offers, which include watching a video, taking surveys or quizzes, or testing out new products. Of course, consider that these completing these offers will take time away from your game time.

Still, there is no arguing about the value of free AP. These AP can be used to purchase a variety of items that will then sell for up to a thousand Gold each.

Sell AP-bought Items for Gold
See below for a rough reference list of what items you can purchase with AP and how much you Gold can sell them for (prices may differ a little based on your server):

Eden Crystals - 100 Gold each
Safety Stones - 200 Gold each
Makeover Kit - 500 Gold each
Memory Tome - 1,000 Gold each

Eden Crystals and Safety Stones
Eden Crystals and Safety Stones are by far the easiest to sell because of their popularity among players. Veteran AP spenders also suggest waiting for the Tiered Spender boosts that allow you to possibly get more items to sell from your AP, although there is a minimum requirement of having 1,000 AP (and you might not be able to wait that long to accumulate that much AP in one go.)

Pets and Mounts
Pets and mounts are also popular choices for their utility and stat buffs, but they tend to have less stabilized Gold prices. To make the most income, you must first scout the prevailing rates for your chosen pet or mount before proceeding with the sale. You can ask more experienced friends and guild mates to help you set a good price for each.

Another great way to set a final price is to first advertise your pet or mount in-game or on the forums. This will get you initial offers, and you can get a feel of how much players are willing to pay. You can even keep a record of the offers for future reference so that you can determine which pet or mount sells for the highest Gold.

Also keep an eye out for what pets and mounts are being requested. Some players will pay a premium to quickly get what they want, and net you a pretty profit. If you are ever tempted to just skip the price research altogether, keep in mind that you might be also depriving yourself of hundreds of Gold from selling a pet or mount at a lower-than-average price.

Bonus Ladders
Lastly, a far riskier but lucrative use of AP is through the Bonus Ladders, but this is not a recommended option for beginners who might not get the optimal number of items, and thus Gold returns.