There are about 400k rough stones sold per day on average on NA. You can go gather and sell them as well if you want to make money.

I did a test with a friend. 

I placed a buy order at a price that no one else had offered. my friend sold the items at the price I had set, the game chose to give the items to another player

If your buy order was not the highest, then you won't get the item. Your friend can decide to sell for a lower price, but the game will actually sell it to the highest pre-order (or lowest price if items are listed below the price you are buying at).  And your friend got the money for the highest pre-order.

So if you want to test this, you need to find something where your pre-order will be the highest.

I am a new player in black desert, I like the game but I have noticed that the market is deficient. 
the prices are restricted by the game and the purchase of the item is rng. which makes the market practically dead and useless

Removing the item restriction would motivate players to farm for economy, more trade in in-game items and pearl market items.

if someone wants to sell/buy a rock in 1b, you should allow it.

the market should be manage only by the players, not by the game. for example, in the game albion online the players manage the economy and the market, the prices regulate themselves due to supply/demand

Hello, I understand your frustration since BDO has a different kind of economy than what you're used to. The central market is designed as such for a variety of reasons. One of which is likely to prevent the market from becoming impossibly expensive. It would create too big of a gap between players. However, you can still make a considerable amount of money using the central market if you know how. There are a variety of changes coming to the market in terms of pricing. They are reguarly being adjusted for improvements. If there are specific items that you would like to request improved, you can leave that feedback and PA will take it under consideration if there is a good reason behind it.

I personally believe a lot of work needs to be placed into revising the prices of the central market and we'll have to wait and see what happens in the coming weeks at the very least. However, I don't believe they will ever change the basic behavior of it so the best thing to do is make suggestions on what to change rather than changing the system in full.

I, for one, actually love the way the market is set up in Black Desert. A max price allows for many things to still be affordable even with the current inflation. Materials correct their prices if they are often sold out, but the rate of it is steady and still approachable.

I would hate for inflation to have its course and make it much harder for newer players to be able to afford, say, Manos gear. 

I did a test with a friend. 

I placed a buy order at a price that no one else had offered. my friend sold the items at the price I had set, the game chose to give the items to another player

When an item is sold the highest bid is filled first.  When an Item is bought the lowest listing is bought first in order of when it was listed or when the order was placed.

When an item is at max price possible for the item, indicated by an upwards arrow next to the price, then it goes to a lottery system.   The person who wins the pre order at max price is random with the only caveat being that if a person places an order for 1000 of an item and they win the lottery and another person posts any number between 1 and 1000 that entire posting will go to that player, if there is any overage then it will go to the next person in line if there is an underage the remaining total on the pre order can win the lottery again but only up until the whole order is filled.  

The inverse is not true, minimum listed items at the absoulte lowest, indicated with a down arrow next to the price, are still in a first in first out scenario.  

My guess as to what happened was, you picked an item that had preorders for a price of say 1000, your friend placed the pre order for the item at 900 you selected 900 and clicked sell.  To avoid RMT listings and prevent selling to a specific person the highest placed order is filled first.

Only max not min.  There is a sell order to min listings.   Next time  you list something at min price, note down how many are listed and how many trades, you will notice that when the number of total trades equals the sum of the number listed at the time of listing and the number of trades at the time of listing your listing will start selling, and the entire stack will sell out.

I did a test with a friend. 

I placed a buy order at a price that no one else had offered. my friend sold the items at the price I had set, the game chose to give the items to another player

That's how it works. And if you placed a preorder at a lower price than someone else, you definitely aren't getting it.