Flipping via auctioneer is a simple and efficient way to make gold. Flipping via speculation, however, is a dangerous and often risky game. In order to help you better use speculation and decide on items to buy for the purpose of flipping, I'm going to show you a thing or two using examples from the current auction house situation.
Saronite Ore - Low Risk, Low Reward
Saronite ore can often be purchased or bid on for close to or even below vendor price. If you were to stockpile this for cataclysm because you want to sell it as bars to alchemists, ore to jewelcrafters or as gems to other jewelcrafting levelers, you would have a very low risk thanks to the vendor option. Even if you are forced to vendor all the saronite you purchased (absolute worst case scenario and highly unlikely), you still would not lose much gold in the process. What's more, you know that the ore will be worth more than the vendor price on the auction house, so you're going to be able to make some gold no matter what.
Saronite's reward looks very promising. Since you will have so many options to sell the ore to multiple professions, I can't see the ore or the results of prospecting/smelting being useless in cataclysm. If anything, golden draenites and thorium ore should teach us that it will be quite valuable, possibly double the current value.
If you don't have much gold or even if you do I would highly recommend stockpiling a decent stack of saronite ore to hedge against the imminent cataclysm inflation.
Mage Armor Flip - Medium Risk, Medium Reward
When glyph of mage armor became uncraftable (bug!), I did my best to let everyone know that flipping these for hundreds of gold was probably a good idea. There was always the chance that the same day blizzard could fix this glyph and it would go from amazingly profitable to nothing more than another mage glyph. The risk was medium and predictable; odds are it would happen on a tuesday so flippers could plan accordingly and attempt to run out of stock close to the next tuesday.
I highly recommend at least trying strategies like this one, you don't necessarily have to spend all your gold on them but giving them a shot is usually worth it.
Polymorph Turtle - High Risk, High Reward
Here's the most dangerous type of speculating. You're playing with fire (as many of you learned with epic gems) whenever you second guess what blizzard is going to do with an item in an expansion or major patch. Polymorph Turtle, eventhough it is going to be available in cataclysm, is still a high risk, high reward item because we don't know HOW the item will be attainable. Will it be a quest, a vendor item or a super rare drop? The last one means that stockpiling the now is a good idea, the first two mean you're S.O.L.
High risk, high reward type speculating should be treated the opposite of the low risk, low reward but many players choose to gamble and put lots of gold into this type of thing. Play it smart, only invest a small portion of your gold into high risk, a medium portion into medium risk and a high portion into low risk.
For ideas on what to stockpile, check out my top ten list for preparing for cataclysm. Remember to apply what you've learned today about risks and rewards.
