The old popular example was the http://www.wowhead.com/item=47257. This item differed on my server from a high of 6k to a low of about 3k. When the price was down at 3k, I would buy a few of these and just wait a week. Throughout the week, I would put in trade and the auction house that I wanted 6k for it. I would then immediately go onto an alt and say that I only wanted 5200g. Sometimes, I would get the 5200g and be a very happy man, other times it would take more patience. However, almost always, by the end of the week, the other sellers had reposted for around what I wanted. This gave me a huge advantage. Now, the price ceiling was no longer 3k on the auction house, but 5k. I could now easily sell the few I bought for 4 or 4.5k, which is a huge 50% profit from the 3k I originally invested.
Okay, this farm really picked up steam here in late legion. Generally what we're looking for is volatile air, and other volatiles when combined with the potion of treasure finding. This farm is as easy as pulling the entire instance all the way to the first boss – and AOE'ing down ebery mob that follows. In the video you can see me getting volatile airs in stacks of 11 for each pull I make. Wit the trending price of each volatile being worth at least 100g, I was making 1100g per pull. It's by far the most effcient volatile spot, but it has hits limits as you can only reset an instance 10 times before you have to wait a while to do it again. If you only going to be on for an hour or so, this is the spot you want to hit. It's great, fast, and awards a high liquid value of items. Awesome Stuff.
Your server population may determine how much profit you can make. Lower population servers generally have lower prices in the AH as there is less demand, but rare items or recipes can really make a profit as they are harder to come by. Higher population servers have a higher demand. However, they are more likely to have a flooded market, which makes items hard to sell, especially in the case of low-level gathering professions.
At 98 you have the option to drop what you're doing and return to your capitol city to start the quest for your Legion Artifact weapon. However, I do not believe this is necessary to do right away unless you're struggling with kill speed in your current gear. I would recommend waiting for a natural pause, such as hearthing to repair and clear your bags. From 100 to 107 you won't even really fight mobs that often; only just enough to clear the way to any treasure you need to pick up.
Blizzard has taken steps in recent years to smooth out out the leveling experience — Legion allows players to immediately boost one character to level 100, for instance — but if you want to roll multiple characters without spending money on multiple level boosters, you’ll need to spend time leveling. Thankfully, with the right maneuvers, it’s possible to level a character to 110 in a relatively short time. Here are some pointers for leveling in World of Warcraft, so you can rush through old zones and explore the new.
Profit is only created if you make sure your costs are less than your earnings. This is not so much an issue for gatherers who simply trade in some time and effort to gain their wares, but for production professions, this must be kept in mind. Many high-end items that sell well require materials that cannot be provided by the gathering profession normally paired with your production profession. To craft these items, purchasing the raw material from the AH or another player becomes necessary. You must keep record of how much you spent to obtain these materials, or else you may price the finished product inaccurately, either too low that you sell it at a loss, or too high that you can't sell it all.