Volatile Fire is quite cheap now but will not remain so after patch 4.3. Volatiles are a cornerstone of the crafting and economic design of WoW, as each one has several types of items that require it for production. When the prices of Volatiles increase, crafted goods go up in price and raw materials go down in price.
Very few people farm exclusively for Volatiles, as they're usually given a small chance to drop off things that are worth considerably more than the Volatiles themselves (like ore veins and elementals). That's part of why the Volatiles market is exceptionally susceptible to changes that change the way a lot of people play and loot. In this case for Volatile Fire, right now a ton of Fires are coming from people continuing to do Fireland dailies. Patch 4.3 is around the corner and will likely have something cooler for people do with their time than grind for entry level raiding and PVP gear. What can you do to protect yourself and profit from these changes?