It's relatively safe depending on a few things. 1, amount of purchase. Spending a couple hundred bucks on dark net markets is not a lot, there for meaning you're personal and LE generally doesn't give a crap about personal. Worst case scenario almost always in the situations is you get what's called a love letter meaning your mail was seized but no further action is taken against you since they would have to start an investigation to try and prove you ordered it, which is not worth doing to someone for a few grams of weed or a couple pills. 2, your OPSEC. You don't just wanna buy a bunch of bitcoins from coinbase and send directly to a DNM address, that's just asking for it. You order small and send to a private wallet first and that pretty much gives you a lot of wiggle room to say you sent the coins to someone for some service and they were no longer yours. Also don't go around telling your friends and bragging about it. If anyone you know asks where you got hooked up, just say someone off the streets. Finally like the first note, buy small and from trusted vendors with good stealth. You're not worth LE's time if you're buying personal amounts unless you ignore a love letter. If you're going to buy bulk you're going to need to buckle down your security, possibly setup a TAILS laptop and make sure you don't order from home and secure you bitcoins from a safe place which is generally localbitcoins. From there you're gonna wanna atleast tumble once for added measure since you're going to be buying an amount worth investigating so you're going to wanna cover your tracks. As I said though, buying small and personal you shouldn't have damn near anything to worry about. Treat your vendors with respect and they'll do the same to you. Also learned how to use PGP as you MUST encrypt your address. No vendor anyways will accept an order with an unencrypted address. The last thing you want is your address clear texted and the market seized.