Dolangmal can send you to Malangdo for free, but only once, you can find him in the folowing locations:
Afterwards, either use the Warp Gate or talk to Odgnalam in alberta,200,151 who will charge 1,000z.
You can enter this instance by talking to the Starfish in mal_dun01 151 235. An Octopus Hunting Stick is required to enter and it will be consumed each time, it can be obtained as a drop from Giant Octopus itself (10% and 35% MVP loot), which can also be found in the Tortuga Dungeon.
This instance can be accessed by talking to Missing, the Cleaner, in mal_in01 160, 34. Don't forget to grab the quests from Albo in the same room, in mal_in01 172 28. Once completed, the quests can be turned in by talking to Madeca who is next to Albo.
For 10 Silvervine fruits, the Wandering Merchant in Malangdo 161 146 will sell you one of the following: