Original Post Date: 6/23/11
In RIFT, you can still make a little platinum by buying low and selling high but it can be quite tedious without mods to help you out.
One method I prefer is to organize AH results by "Time Left" and bid on items that are just about to expire. Crafting materials are the best, such as buying cloth and ore at their lowest (vendor) price. You only need to check the AH for new groups of expiring items every 1-2 hours since you will receive mail messages if you are undercut on the ones you have already bid for. I like to bid on items right before a shard reboot as well, it increases your chances of winning the item.
The other method is to buy items simply to vendor them. In WOW, there used to be a small profit to be made from buying low-cost bandage mats, and then vendoring for a profit. However, RIFT is a special case and large profit can be made from vendoring items that auction for less than their real value.
Search all AH items and organize by Unit Price. Then you mouse-over on each item to see what it vendors for, and compare to the Unit Price value. Bid or Buy Out any item that is being auctioned for less than the Vendor price.
In the following case, there is a profit to be made of 28s x 13 Celestite. This is not a lot so I usually target more expensive items but imagine 50-100 transactions per day giving you 1-50g per.
This occurs far more often than you can possibly realize. Some players are in a rush to auction multiple items, so they don't pay attention to the item's true (vendor) value. Others are in competition with other players and keep undercutting their prices, or they're sick and tired of an time not selling (especially runes) so they keep lowering it's price without realizing they can make more plat by just vendoring it.The best items suitable for this method are gems, herbs (Krakenweed), Consumables (Potions), Runes, Scrolls & Armor Enhancements/Consumables, and Crafting Ingredients (like Pristine Femur and Hollow Bone). You can get the most bang for the buck with stackable items.
Each day, I can make 6-10p by just vendoring buy-out items. :)
It works better on larger population shards as well. On new shards, players are much more careful because they're more concerned about saving money.