Invest - If you do not plan to rush to level 60 and want to take your time instead, this tip might come in very handy for you. The value of many Items will increase over time because more and more Gold will find its way to the market. To take advantage of this, you can stack up on various crafting materials with the intention of selling them on a later date. This will require a lot of patience and some Grinding if you want to make a good profit but is certainly worth your while if you are an economy-oriented Player.
That's not to say that everyone has an unrealistic vision of what vanilla WoW was like. There were already plenty of people on the WoW Classic forums pointing out that perceived bugs are just recreations of the original game. And as noted before, a flaw to one player is a key component of the original positive experience to another. WoW Classic will surely please plenty of purists in spades. But this goes to show that it won't be for everyone who has fond memories of the game circa 2006.
*If you run out of Bag and Bank space on your Alt, fear not, as the Mailbox itself is a great place to store your Items. Just mail everything to your Alt and keep it in the Mailbox. Expired parcels will be automatically mailed back to your Main, so you will not lose any items and be able to Mail everything to your Alt again (Mailing items cost some additional Gold, but the amount is negligible when compared to the utility provided by almost unlimited storage space).
WoW Classic seeks to recreate the "vanilla WoW" experience—that is, WoW as it existed before a series of seven game-altering major expansion packs from 2007's The Burning Crusade to 2018's Battle for Azeroth. To achieve this, Blizzard has rebuilt the game based on archived data from back in 2005 and 2006 (patch 1.12 is the goalpost—the current game is on patch 8.1.5). The company has committed to meticulously presenting the experience exactly as it was back then—warts and all—with only a small number of unavoidable or critical changes.