http://dancesafe.org/products/testing-kits
http://bunkpolice.org/
But testing kits. I can't emphasize that enough to kids. If you go to shows and do "molly" buy a fucking testing kits. You can test 50+ times easily with one vial.
Get a marquis test. It's very simple with powder ecstasy. You only need the tiniest bit and one drop will react. Take the clear plastic top from a water bottle as it's solid but not colored to throw off the test. Take a very tiny scoop, like as little as you can. Maybe a like much less than even a 10th. Now you put one drop from the vial into said cap and wait for the reaction. Be careful not to touch it or spill any of the vial on your body as it is corrosive. Just a heads up, not trying to make it sound super dangerous as it's quite simple to use.
If it turns yellow WALK AWAY, and warn your friends. I mention yellow because that's what you'll find the majority of the time. You're looking for it to go dark purple to black. If a tiny crumb sends it instantaneous black you found what you want.
Don't let the price be the main factor, especially once you have a tester kit. Paying 40 bucks more for something that's real and safe is far better than spending less on a random chemical.
On the marquis, a purple/ black will mean what you have is MDMA or MDA, you can use a further kit to determine which of the 2 you have but both, though slightly different are very much real.
If you have a group of people that buys stuff regularly, it's worth it to at least get one tester kit between you guys.
Your health is worth paying 20-25 bucks for something that will last you a while. Also feel free to help out strangers. We're all in this together and nothing will change for the better until we start doing this as a whole.
Hell I don't even do drugs anymore. It's been years since I've been into any of this stuff, but I just want to make sure people are alright and stay safe out there.