VisualRebel picked up on one of my earlier posts found here about cheap ways to shoot Macro. I'm not sure if anyone really believed the quality you can get from flipping a lens backwards, but the proof is in the pudding. This video was shot by VisualRebel using a standard 18-55mm on a 550D / T2i, and handheld used the cheap $99 dollar 50mm F/1.8 in reverse. This awesome little video does a good job in showing the quality of Macro with equipment you probably already have. Now take this setup outdoors with more light, and get in on those creepy crawlies like National Geographic.
Here's a tip folks, if you want to use the exact same setup as VisualRebel, the filter on the 18-55mm is 58mm and the 50mm filter is 52mm. You can buy this special adapter for less than $4.00 dollars + Free shipping to 'mate' the two together (one in reverse) so you don't have to do any handholding. Save yourself the headache. For less than $4.00 + Free shipping, you can get this adapter to hold the lens for you.
I'm not sure what's the best combination of lenses to do this reverse trick, it's more trial and error. Apparently this video shows superb quality and definitely sounds like the cheapest (and lightest) combination for reverse macro. You can find other Rings here to match different size lenses against other size lenses by clicking here.
If you've already got two lenses to do reverse Macro, then the adapter is cheap. If you're looking to simply work with 1 lens, especially the 18-55mm, remember to check out my review on the cheap Macro Bellow found here: