Im pretty sure most countries have their own systems and websites. I dont think anyone really uses silkroad and those you had years ago.
But you might not need to use darkweb in many countries. For example it took me like 15 mins to score pretty good hash at Frankfurt central railway station when i visited there. I got like 1.6-1.8 grams for 20 euros, some countries you can get cheaper and in some you need to pay 20€ per gram for weed or hash.