Anything that can be answered by reading the recent discussions on the subreddit, has a yes/no response or can be looked up on sites in the community resources should not be posted in a thread of its own. Questions such as 'What is this worth?', 'Did I make a mistake?', 'What do I do with XYZ?' or 'Should I buy/sell this?' will be directed to the Daily Questions sticky.
Weak Auras is the most important AddOn for players seeking to master their class and take their gameplay to new heights. If you aspire to do any Mythic raiding, this is the most powerful tool in your kit. Weak Auras allows you to display helpful visuals cues anywhere on your screen, which enable you to play better. Most players use it to track their trinket procs, highlight on screen displays of their most important cooldowns, or track the timers of boss mechanics. It is highly customisable and makes keeping track of your procs and cooldowns effortless. The drawback of Weak Auras is that is has a bit of a learning curve and is not the most user friendly. Weak Auras allows you to import other players data directly into their UI, however, and most players choose to simply import other people's Weak Auras rather than make their own. Weak Auras can be used to create just about anything you can imagine, as it is a LUA scripting tool (essentially an AddOn that creates other AddOns, in-game). This is by far the most essential AddOn for players looking to step into Mythic raiding.
AWESOME spot.. if you are a druid, here's why.  This spot takes place on an island in the very north part of Stormheim, which is surrounded by water.  In this water are 2 groups of crabs that roam in packs of 12.  Each of these crabs can be skinned for scales and with the usual perks I mentioned in the earlier skinning spots.  (See spot 13).  The only catch is sometimes the crabs are very far apart and require some travelling to get to.  Druid travel forms not only have increased swim speed, but the wild charge ability allows you to swim 150% faster for 10 seconds, all the while replenishing your breath meter.  Pretty cool right?  I found that druids are AWESOME for farming this spot and can easily outclass other farmers here.  It's a druid spot that limits the competition – while ensuring you have the most uptime.  Very cool.  Gutting and level 3 stormscale skinning recommended.
Enchants. I honestly wasn't 100% certain which enchants were best, since scaling has screwed up a lot of things. IMO, just pick the enchant for each armor slot that has the highest bonus without level restrictions. The exception is that you'll definitely want Mark of the Hidden Satyr for your neck piece, and probably Elemental Force for your weapon. Both of these proc consistently and strongly across all levels.

First of all, the value of transmog is decided by rarity and how they look. Some items like Minenarbeithut der Tiefen or Pendel der Verdammnis (they can drop in Uldaman) are worth millions of gold. They are worth so much, because they have a really small chance to drop. Other items are bought well because they look good. Best example in this case is the Glorious set, its legplates Glorreichen Beinplatte reach a 100.000 Gold value easily.