Some Developer replies from players asking for an "auction system" (Search for "auction" if you need to see more)
The sort of thing you're asking for would be great, but it isn't something we want to develop. The potential cost of completely overhauling the entire economy of the game is too high and far too risky.
Not sure about the "whole picture", but I do see enough of it to tell you that it isn't going to happen.
How long do we store data? How long do we store it for?
Do we piggy back the existing inventory system, or write something new? If we leverage the existing, we have to lock items out of the loadout system. If we build a new one, then we have to manage that as well.
How many items do we cap it at? Can't be limitless or it will break the database.
How do we define prices of things? - if we use items, what quality of items? How do we define that and show it in a meaningful and easy to understand matter? We can't use fuel because then people will farm fuel into main accounts and everyone else will get angry.
You need a messaging system to let people know that items have been taken as well - but what about people that haven't been online for a long time - do these messages just build up? Do we cap them?
Then you get into the really hard stuff - data synchronisation / asynchronous operations / race conditions.
You log in, start looking through my items which causes you to load up all my items - mean while I log in on a different server and start changing my data. Then someone else has a look at the same time. Now we have the issue that any of us could have changed something and we all have out of sync data.. items getting duplicated - other items getting lost. But we don't know what because we aren't actually talking to each other.
The only way around that would be to spin up a new room for every person every time they log in or someone wants to look at their data - which is a lot more load on the servers for something that 'might' me looked at.
I'm sorry to shoot down your idea, but as other have pointed out it has been shot down in one form or another many times before. There is a reason it is the way it is and it is to get around a lot of these issues.
Sorry but no.
Sorry to be the bringer of bad news, but this is never going to happen.
First of all, the "tax" is there for a reason. It is to stop (or at least slow down) people using alt accounts for farming, etc. If you could move resources for free then we would have a lot more people setting up second and third accounts to feed into their main account. By having a tax and limited slots they have to put effort into the other account.
Secondly, whilst I like the idea of being able to post items, also posting what you want would just be a logistical nightmare. Eg: You want to trade X for Y... what version of Y? What level? Is it a minimal level, or a specific one. Is it a unique? How do you know it is one you want, as they are all different, etc. The thought of catering for all these possibilities is enough to make me want to run and hide.
Then you have the problem of approval.
Auto approving a trade for you is fraught with danger for a bunch of reasons. I would hate to see the back lash if it wasn't 100% accurate all the time.
Getting you to approve trades.. maybe that would work, but I imagine there would be a lot of spamming, etc. Do you put it up, then wait for someone to accept, then you approve? That sounds like it may work, but what 'state' are the items in? can you use them? are they locked.
Eg: you put up 500 water, but you haven't been online for a while and now you don't have that. What if the other person no longer has those items in the time it takes you to approve it? Do you stop the whole trading process? do you take out the items out of your inventory straight away? if so then that becomes exploitable unless you limit the number of trades you can put up.
These ideas are just off the top of my head. I'm sure I could think of more if I really thought about it.
P.S. Admittedly I didn't read the whole thread so sorry if I covered something someone else already said.