The material costs are usually unbelievably low, meaning you can buy the raw materials from the Auction House and there is no need to prospect. Sometimes it's the other way around, and the gems are selling for 50-100g each. In this case it's often wise to prospect these gems and sell them as they are.
What to create and how valuable are they?
All of the level 29-65 rings are useful. It's a good idea to create 2 of each rings and one of each amulet and see which sells fast.
From my experience the following have been selling the fastest, and I've usually been the only one selling them, save a few exceptions, so they are also the most profitable for me.
- Aquamarine Signet
- Simple Opal Ring
- Diamond Focus Ring
- Emerald Lion Ring
- Necklace of the Deep
- Living Emerald Pendant
- Sapphire Pendant of Winter Night
- Amulet of Truesight
- Aquamarine Pendant of the Warrior
- Band of Natural Fire
- Onslaught Ring
- Sapphire Signet
- Truesilver Commander's Ring
Some have sockets in them. Put some red gems into them and you can raise it's price by even 200g!
I never ask for less than 50g a piece. Depending on how valuable the materials are, I sell each for 50-400g and they all go within a few days usually, especially the ones with a lower price tag on them.
There are exceptions though, such as Aquamarine Signet which has a random enchantment on them. This could give crappy stats, such as agi and spirit, which is not a very nice combination of stats. I usually sell these for about 20g instead.
Check level 10-16 items aswell!
There are times when there are none of the low level jewelry for sale. These items sell the fastest, so if you get the chance, this will make you rich! An example ring would be Inlaid Malachite Ring. I've sold many of these for even 40g each, even though they cost about 90 silver to make usually!
Not sure which ore prospects into what? Do a wowhead search and check the prospects into tab!