Saronite ore is one of the main crafting materials in world of warcraft and thankfully blizzard made it fairly easy to stockpile while farming or else prices would be ridiculous for many items, including titanium bars. Here is a quick chart of how to use titanium bars to make gold.
Buy Saronite Ore on the auction house, Smelt into Saronite Bar, Transmute into Titanium Bars, and finally Craft Titanium Rod, Titanium Weapon Chain, Titanium Plating and Titanium Shield Spike. You could also smelt titansteel.
The real trick to this is getting cheap saronite ore, which on most servers is just a matter of checking the auction house every time you log in. For every stack of saronite ore you will get 10 saronite bars and 1.2 titanium bars before alchemy transmute specialization.