The way we get our beer is changing. Your supermarket has roughly a bajillion brews for sale, and your local beer bar has approximately a bajillion more. But what if you want the rare stuff? A bottle that's only sold at a brewery 2,000mi away, or only once a year on a date that coincides with your wedding anniversary? What then? You trade for it, that's what. There's a vibrant gray market for beer, and it lives on message boards. That's right, you guys: not only are the files in the computer, but the dry-hopped IPAs are, too. The thing is, craft beer's digital swap meets can be a bit daunting for first-timers. Hell, they're a bit daunting for me, and I write about this for a living. So I tapped my beer-trading buddy Thomas Haydon to help me create this very primer. If you're looking to get into the sort-of legal world of shipping stouts across the country to get other stouts in return, let this unofficial, incomplete guide to beginner beer trading light your way. Cash is not king. Nobody wants your cash. Perhaps the most surprising truth about beer's thriving, semi-legal marketplace is that actual money rarely changes hands. "This isn't so much an unwritten rule, but I think it's the most important foundation of the beer-trading community," explains Haydon. "Beer trading is all about the beer-for-beer transaction." The craft community is famously tight-knit, but there's another reason for this rule besides friendship. "Trading for cash is illegal... on top of shipping alcohol," says Haydon, which, depending on which states are involved, may also be on the wrong side of the law. (More on that in a moment.) Listen before you speak... In beer trading, as in life, it's smart to keep to the sidelines while you're figuring things out. "Before getting your whistle wet, monitor the boards for a few days to see what people are offering vs. the beers you have access to," says Haydon.