Just go Jewelcrafting & Transmute spec Alch, easy money maker especially after resets and even more so after new patches. Like an easy 10k a day if lucky and 20k after patches
Varies by server of course...
Pandarian Garnet - 2g
Golden Lotus - 60g
= 62g Primordial Rubies (and with transmute spec you get a lot of freebies)
Right now on my server.
Primordial Ruby - 80g
Bold cut - 88g
Delicate cut - 112g
Brilliant cut - 120g
I don't prospect anymore, way too time consuming, I play the transmute game to do my cuts. Transmute 200 gems, afk for 5 mins, cut 50 brilliants, afk a min etc. Prospecting you have to press a button every 5 secs, f that.
If you want to add one more character into the mix, I would go with Blacksmithing and Mining. Mining because you can gather while doing shit, and smelting is awesome, I was making 10k a day off it from wrath-cata ores after 5.2. Also helps you make ghost iron bars which you can feed to your transmute spec alch to make trillium and living steel.
Blacksmithing because you have all this ghost iron, can also turn living steel into buckles and weapon chains.
Don't touch inscription, that shit sucks yo even though I'm doing okay from shoulder enchants and darkmoon cards/trinkets. I milled so much shit at the end of cata for MOP, and while it paid off when the AH was bugged (listing the most expensive first, so I listed like 15 of each lol), I have so many left over inks off everything left over.
And Just my two copper has been shit for years since the original owners sold the site, consortium forums is the way to go.
Learn the MOP Blue market if you want something quick and easy as long as you have enough startup cash to fund it. Because you're less likely to get some bargins under 50g these days and instead have to purchase @ like 1k to flip it at 2k. But you need to learn your market and it's prices to do that, I've been doing it since the start so I know whenever I see a Zom's Misty Hood on the AH for under 2k I can buy it and it will eventually sell @ 3k. And you need to be patient and let the item sit until it sells, no panic.