What’s Selling (ymmv)
stargrace 
Everyone is going to have their own particulars for their own server, so you have to take this with a little bit of ‘your mileage may vary’ – just because these things sell on my server does NOT mean they will sell on yours. That being said, there are trends that carry over from server to server. This graph and these sales are the past 7 days.
My number one seller was elementium bars. I sold 1001 of these for a total of 74,565 gold alone. This is most likely because of people leveling up their cataclysm engineering, the loot a rang that is so popular with multiboxers requires 70 cataclysm engineering, and it’s not cheap to get done. Past me is very happy to have picked up those bars for 3g each. I also sold 1093 ghost iron bars for a total of 54,579 gold, and elementium ore, 451 of those for 32,163 gold.
Next seller, is the Highborne compendiums – in specific, storm. There was a Wowhead article about how this trinket is BiS and things just took off from there. I sold 7 of these, for a total profit of 42,751 gold.
In that same line, inscription received three new glyphs when the pre-patch landed, and not everyone has picked them up yet. They don’t cost any more than regular BFA glyphs, but you can charge a premium for them because they’re new. These glyphs are ‘of the aquatic chameleon’ (41,326 gold, I sold 17), ‘of the aerial chameleon’ (33,254 gold, I sold 16 of them), ‘of the swift chameleon’ (31,826 gold, I sold 15 of them).
A handful of transmog (29k worth), a few mounts (only one jeweled onyx panther this week), and a lot of rings – BFA rings really took off, and I just restocked yesterday. I also sold 13k worth of recipes, which is always nice – it all adds up!
Those fish cakes I started selling? I sold 15 of them this week, and made 2,806 gold from that. It’s a really simple craft that just adds to the pool.
As always, happy gaming, no matter where you find yourself!