The answer to this is simple.
Here are the conditions of the event:
- You are supplying all materials, including fuels (vials, threads, etc).
- You are going to the crafter, wherever that may be.
Given the above conditions, the crafter isn't losing any money or losing any travel time or being inconvenienced due to travel limitations (hearth cooldowns, teleport costs, etc). Therefore, no charge should be indicated for these conditions.
The crafter is giving up the following:
- The time to reply to you agreeing to craft the item.
- The time it takes to trade the mats to the crafter.
- The time it takes for the crafter to locate the recipe and combine the mats.
- The time it takes for the crafter to return the finished product in trade.
If we were to assign general estimates to the above time losses to the crafter, we may consider 10-20 seconds for someone to reply, 30-60 seconds for the crafter to receive the materials, 5-50 seconds to locate the recipe, 5-60 seconds to combine the materials into a product, and 30-60 seconds for the crafter to return the finished product and receive a "tip".
This results in 80-250 approximate seconds that the crafter gives up in time costs. These are opportunity costs, where the crafter may have been doing something else during these seconds, other than crafting the item for you. Reasonably, the average amount of coin a player may gain from killing a mob at level 80 would be about 30 silver; if this player kills a mob every 10 seconds, they could make 1g 80s every minute. Thus, if it takes 250 seconds to interact with you for the crafting of an item, the player could have theoretically made about 7g 50s, or we could round it up to 8g.
As a result, I declare that 10g as a tip is more than fair for any crafted item, no matter it's level, type or rarity, given the above conditions.
Things to consider:
- Some crafting requires physically located objects such as an Anvil. This adds additional time, because the crafter must go to that Anvil.
- Some crafting requires the sub-crafting of materials before the main crafting occurs for the final product. This adds additional time for the crafter.
- Some crafting requires charges/cooldowns that may limit the crafter from performing the function again for some time. You may want to tip more for this. However, a good crafter dealing in popular items will burn these cooldowns each time they are available, with or without a customer and have them on hand.
- Nobody told a crafter to obtain a rare recipe. Nobody held a gun to their head and told them that they had to obtain some rare recipe. Therefore, the rarity or possession of the recipe itself bares no logical weight on the tipping factor.
- Obviously there are things that may affect the tip you (as the customer, remember that factor) give. For instance, if the crafter responds clearly and directly, doesn't act confused, knows up from down, etc you may want to classify them as a 'good crafter' and give them more of a tip than average. However, if a crafter acts overly confused, massively delays in response, acts like they just don't care if they have you as a customer or not, etc, you may want to give them less than the average tip, if you even deal with them at all.