Guild Wars 2

What is the cost to make a legendary (in gold, karma, badges of honor etc…)if I bought as much stuff as possible from the TP including the materials for the precursor?

If you go here, they give you the basic rundown of what is required and how much everything costs.

https://wiki.guildwars2.com/wiki/Legendary_weapon

http://gw2legends.net/

This site allows you to select your weapon, and has a detailed break down, and uses live market data to get you costs etc, you can input what you currently have and it tells you what you still need gold wise.

This does not have any of the new weapons yet as well no one knows what they need.