Your level 45 toon could make a lot of World of Warcraft gold even before he reaches the maximum level. Best of all, you don’t need to spend all your time farming. 1 to 2 hours of farming a day would be enough time. You’ll have time to spend outside Azeroth and do normal human stuff like eating perhaps.
If you want to farm at this level then head to the Hinterlands and find the Vilebranch Trolls. Their levels range from 43 to 50. There are some elites mixed with the crowd so be careful of what you pull. They drop a lot of stuff but what you’ll be looking for is the Wildvine. This herb sells for 1gold each. The Wildvine drops 1 in every 10 Trolls killed.
You might be asking why it costs that high. It is used to make Wildvine Potion that restores up to 1,500 HP and Mana. It is also by Blacksmiths, Tailors, Engineers, Leatherworkers, and Enchanters to craft items. Wildvines are required for two Leatherworking quests. It is such a useful herd that’s why it’s in demand even at present.
The Vilebranch Trolls have other valuable drops. Alliance players can turn in Troll necklaces for a repeatable quest. They also drop money, Mageweave and Silk cloths. The cloths could fetch a couple of gold in the Auction House. Plus they would drop the occasional green and blue items. You can have them disenchanted or sold at the Auction House.
They would also drop Flask of Mojo. Since The Burning Crusade, Flask of Mojo value has risen. These days it could be sold in the Auction House for at least 1gold each. Jewelers need Flask of Mojo to craft Aquamarine Signet. Leatherworkers and Engineers use these as well. Just like the Wildvines, the Flask of Mojo is another money maker from the Vilebranch Trolls although the drop rate is a bit down.
The Wildvines from the Vilebranch Trolls could be worth the grind you spend here. Plus if you’re Alliance, you can turn in the necklace from the Trolls at the entrance of Aerie Park. 5 necklaces give you 390 XP. As always, this is gank territory. For those in PVP servers, be sure to watch your back. If gankers are in the area, it is best to look for other farming spots. It would be not worth the effort if you are always in ghost form.