Well the point of the black market is pretty much like stock exchange today you buy when the price is low and sell when the price is high you can get serious coin by selling resources at the right time. When you want some more cash and the prices on resources and demand is high you place items on sale like crystal and metal. Other players will buy the resources thatyou offer and you get the money directly. Although I usually do not put items on sale because my enemy can by them build a kick ass fleet and boot you in the ass when you're not looking. So I would just stick to selling and buying at the right time. Hope this helps.

Yes you can buy resources on the black market from other players. The only time you should put resources on the black markt is when the price is high. In multiplayer you can buy resources from a player when the market price is too high, but the money that you pay will not go to the market but to the player that you buy it from. I only put resources on sale when I feel sorry for the poor guys, but usually I don't because like I said if you give resources to an opponent then he can build a fleet with it and kick you in the ass later on. When going against an AI you can get serious money off of him but still only do that if he has a small fleet or you have a surplus of resources. So in the end yes it is to undercut and crash the market and to buy resources directly from a player. Hope it helps

Ahhhhhhhhhhh....Forgive me for being thick, I should have made this realisation earlier. Most people will already have clocked this but I will post this for anyone who hasn't yet. Apologies to noobinator - i can tell this is what you were trying to say all along.

When you buy and sell resources on the Black Market screen, the price for buying is on the left (usually around 450 or so) but the price for selling is on the right (about 250 or so). The left side (quick-buy price) is the MARKET price but the right hand (quick-sell) price is only about 50% of the buy price. So if you sell via this button you basically get only 50% market value cash back.

BUT... If you put your extra resources for sale on the Black Market at the bottom of the screen for people to buy direct, you can name any price you like up to 100% FULL MARKET PRICE. So you get way more cash for your metal and crystal than if you 'QUICK-SELL' it.

So as noobinator says, if you buy low and sell high DIRECT, you can get some serious credit from other players and the computer because is you were to offer your spare resources for 90% market value, that's cheaper than the 'QUICKBUY' for the buyer, and you get 40% more than 'QUICK-SELL' price. Everybody wins, especially you!

All this wasn't immediatly obvious to me but then i'm not a financial person. I hope this helps other new-to-the-game players.

Even in 1v1 games you are better off selling at 98% (or lower) than using quicksell.

Question on this because I'm still confused. Will the AI buy your goods? I'm playing a single player game and I put 2000 metal in the market and set the price to 4.1, however, the metal is still there and I can take it off after a couple of hours. If the AI were buying it, it would disappear, right? That's why I was wondering if the AI actually buys the goods?

They usually don't buy them unless they really need it.  Sometimes I do both.  I put couple hundred resource on black market and then sell some directly.  Sometimes it takes too long for the AI to buy the resource.

But, it will disappear from the stock you've put up there, right?