If possible, avoid purchasing Gear from the Auction House - Ideally, you should be able to achieve level 60 without buying anything from the Auction House. This way you will save Gold, but possibly make leveling a bit harder for yourself. If you badly require an Item upgrade, and the suitable Item is available on the Auction House for a low enough price - buy it, but only if you think that the investment will pay for itself in one way or another (the main exceptions to the Auction House ban Rule are Weapons and Wands, as they make leveling much faster, and pay for themselves by allowing you to chain-kill more mobs without Eating and Drinking, which saves Gold and time).
Hey buddy, I think you're forgetting that wow is part of a company and it's one of their major products they've been relying on for years. You may hate BFA and all the people who are still subscribed and playing BFA, but I can assure you Blizzard doesn't think that way. Imagine you sign up to go on a brand new cruise ship. The cruise ship company has a bunch of loyal customers who have been going on their cruises for years so they let them tour the new cruise ship the day before, however they decide to let new customers go on the tour for a small fee if they want to. That's what this is like. They're giving a little kick back to all the people who have stayed subbed to wow. I haven't played wow since the middle of legion and I can totally understand why blizzard would do that. You may think classic is all that matters. Blizzard still cares very much about the BFA players.
Some players have been surprised by these apparent flaws—even players who have been eagerly awaiting WoW Classic's release based on fond memories of vanilla WoW. In truth, it has been so long since WoW first released, players' memories may not always be accurate. Some details might be fresh, but others might be lost in time, and it's those lost details that could surprise players revisiting the original experience in WoW Classic.