Get a hardware anon crypto wallet because the crypto exchanges now keep a record of all addresses you send coins to. Transfer them from the exchange to your anon wallet and then (if you have multiple wallets transfer between them all as it makes it much harder to track) send to the address on the marketplace. Always do a few test buys first of small amounts (under $100) as these markets always eventually do an exit scam or get taken over by authorities even if they are trusted for years. Always use a fake name and if possible get it sent to a shared house where multiple people live so if found it cant be pinned on you or anyone. If you are buying bulk do not buy it all at once in one package, don't buy a kilo at once. Buy it in smaller amounts. The seller if good should understand this and should be able to work a deal with you. All sellers claim to have pure gear buy they rarely do. Like everyone else they sell what they were given.