Keep in mind that these quests are optional, and are not necessary to continue leveling and capturing companions. They are also account-wide, so if you complete the quest chain on one character, you will not be able to complete it again on another. However, any progress that you've made will be saved and you can pick up where you left off in the quest chain on another character. The dailies that you've unlocked will also be accessible by all your toons.
The Auction House is always the best option for getting good equipment at a good price. The only items you should be buying from Vendors are basic consumables: food, drinks, arrows, bullets, vials, dyes, etc. Most other things should come from the Auction House, as they are generally cheaper. Keep these tips in mind when buying items off the Auction House:
Improper leveling of your production profession skills can cost a small fortune. Heck, even proper leveling of some production skills can cost a small fortune. And keep in mind that equipment you produce using your profession will typically be slightly worse than equipment otherwise obtainable at your level via the Auction House and/or instances. It is therefore strongly recommended not to take on a production trade skill until you hit at least level 30, or better yet, level 70+. However, if you are determined to take on such a profession (particularly under level 30), read a suitable leveling guide in order to gain whatever skill level you desire for the least amount of money.
The most important part of saving is to never buy equipment unless you're positive that it will increase your earning potential, or significantly speed your character's leveling progress. While it is true that gear is important (particularly for melee combat characters), it is also true that an overemphasis on having great gear before maximum level is dumb. Who cares if you're wearing a green sword at level 43? If you're advancing well, you aren't going to be level 43 for very long anyway. The only gear that currently "counts" is max level gear.
There is a constant market for transmutations. If you are capable of doing these, you can charge an upcharge on each of those transmutes. A player who logs on his/her character each day, and sticks to it, can generate a significant subsidiary revenue scheme through transmutes. Likewise, if you have a transmute that allows you to transmute a lower value element (such as Earth) into a high-priced one (like Water or Fire), you can make a cool 15-20 profit every day by simply doing your transmutes.
Beyond that the constant amounts of RNG on top of RNG has made the game not only frustrating but unfun and unrewarding. It is clear with the current game design decisions the goal of bfa was not to create an exciting experience and to refresh world pvp and faction pride, but to test the player base and see how long subscriptions could be pushed with the least amount of content. Class specific raid gear, tier sets, removal of any sort permanent player progression and a complete draining of class skills has left BFA with less and forced players to grind more only with the knowledge that like Legion all your work at the end of the day will be worth nothing due to end game catch up mechanics and removal of the azerite necklace at the end of the expansion.
Island expeditions are very easy to complete while leveling, particularly before hitting Level 116 when your legendaries are still in effect and your secondary stats have not been squished by leveling scaling yet. Island expeditions can be completed in 5 to 10 minutes relatively reliably while also acquiring some of the pets, mounts, and Bind-on-Equip gear available. There is also one weekly quest to do one island expedition, so for slowly leveling alternative characters, be sure to complete at least one island expedition each week.
A dungeon should take about half an hour to 45 minutes, that is reasonable. What did we do to Maw of Souls because it was by far the fastest dungeon to spam run for AP? Nerfed its yield. Same happened to dungeons. Except instead of nerfing the XP, they adjusted the clear speed to justify the experience a bit more. Is it perfect? Nah, a lot of dungeons aren't even that long with updates. At most a clear takes 5 mins more.
Be aware of the seasonality of items. Check what items are used in seasonal achievements, such as Delicious Chocolate Cake or Small Egg during Children's Week. When the Darkmoon Faire is in season, Darkmoon cards and decks (Furies, Elementals, Lunacy, etc.) tend to sell well, but prices also tend to get depressed. When the Faire leaves, prices return to normal, but sales volume decreases. The same is true of things like Snowman kits, Red Holiday wear, etc. Holding onto that Snowman kit for a few months, and then listing it in July, can net you a significant profit.
From “The Burning Crusade” expansion, weapons like Klinge der Zauberei, Die Nachtklinge and recipes for different weapons are really valuable. The best example is Pläne: Teufelsstahlangschwert, worth 500.000+ Gold. These items are World Drops, you can find them in all raids and dungeons. I don’t know any Open World Drops, but that does not mean there are none. Another great transmog source are world bosses and rare spawns on Outland.