In my day it was all about thorium ore, you young whippersnappers! I played to TBC but quit by WOTLK, though I did briefly give it a go but don't think I got max level.
At the start of the expansion Monelite Ore sold on my server for 185g each, but this basically in the first week. Normal price became around 70g, but now the average is 37g each, but this is also weighted by the first weeks high prices. Try TSM4 if you are interested in making gold efficiently rather than selling things at the lowest price. Its not an easy addon, but a few YouTuber's show good guides. The mats are used for Armor, or Turn-ins for quests or just leveling up professions on main and alt characters.
Yeh I have TSM, what a life saver! Wowww what server are u on lol that is amazing. Even in BFA launch in mine it was never that high at the start. They got for about 28g each now and nearer launch they were about 78g each. My server is medium ish pop I think. It's always been my obsession to play WoW for free and I enjoy trying to make gold so if I can I will but sometimes it's so time consuming and dull (sometimes) that I think, just pay with real money and enjoy the game haha. I've made quite a bit over the past week though, things seem to be selling again.
out of interest what prices were u selling let's say a full stack of 200x monelite ore and stormsilver ore for nearer BFA launch and how much do you sell them for now? I just sold a few stacks of 200's and I can confirm you get a lot of gold but my next question was "Ok...if people buy them for this much, what are they doing with them and can I make more by doing the same?" however at the moment even though I am aware of this I am currently too lazy / unwilling to put the time in yet to figure that out and level other professions lol. Plus I seem to be getting hundreds of the mats without even realising. I look one moment and I have hundreds...sell them look again a few days later and I have loads again!
Play hard with gathering professions, learn the Auction House with addons and earn 180k gold a month and you play for free. In the first month of BFA I have earned around 1m gold, but the prices on the AH were good at this time and playtime tokens have been currently low at 175k (previously 300k ish).