It doesn't matter if you rely on your own mine production or if you steal the resources from other players, those will almost never be the exact amount you need for construction or research. Here comes the possibility to trade your resources, for example to compensate your lack of metal with your deuterium surplus. You can do that by trading with other players or by using the merchant.
The classic trade
When doing a trade with players, both of the trade partners send the predetermined amount of resources to the other player. Because of that, not only the amount of resources but also the coordinates to which they are to be sent should be arranged. An arrangement according to the delivery time is advisable also, so that the trading fleet does not arrive in the middle of the night and the resources do not lie around unprotected for hours.
Basically trading must comply with the rules. Resources should only be traded in such a ratio, where nobody would benefit exceedingly (at which only an advantage of the stronger player will result in consequences). Normally the ratio of Metal, Crystal and Deuterium is between 3:2:1 (that means e.g. 300 Metal to 100 Deuterium) and 2:1:1 (e.g. 100 Deuterium to 100 Crystal). Furthermore a trade must be finished within 72 hours; otherwise the responsible game operator must be informed about the delay using Ticket system guide. If the trade is not within the legal trade rate or is not finished in time, the GO might ban both acounts for pushing.
Where do I find trading partners?
Asking your own alliance or friendly players is the best and most secure method. They often give you a better rate than foreign players and the danger of being cheated decreases, because basically it is not forbidden to cheat the trade partner.
If you are not a member of an alliance or if there is nobody who has the resource you are looking for on sale, the board will be a good place to trade. In the forum and there in the sub-forum of your universe, in the trade forum, you can open a new thread and present your offer. There you should specify the amount and type of the wanted and demanded resources, as well as the ratio and the galaxy, in which the trade shall take place. Potential buyers will contact you in the thread or ingame, if you give out your contact information. You can also respond to the offers of other users, but please check if they aren't already done and the thread starter has asked for a closing of the thread.
How do I use the merchant?
If there is no human trade partner or if nobody has the wanted resource on sale, you will be able to use the merchant, who you will find in the main menu under “Merchant”. There you can call a Merchant, who trades with a certain resource, by clicking on the according button. Calling the Merchant costs 3.500 Dark Matter, which will be specified in the chapter Premium features. You can also find merchants on Expeditions, however those only buy a certain resource, which is possibly not the one you want to dispose of at that moment. If you find a Merchant while another Merchant is already active, the located Merchant will buy the same resource as the present one, only the ratio will change.
If you have decided to use the Merchant, the window on which you can trade the resources, will appear. There you can see the ratio for the first time, this is assigned coincidentally, but it is mostly under 3:2:1. If you are not pleased with this ratio, you will be able to call a new Merchant; doing that will make the old one disappear – you spend another 3.500 Dark Matter. If you are pleased with this ratio, the trade can begin. Because the Merchant will stay until you either use it or call a new one, you can take your time.
For example, if you call a Merchant, who buys Deuterium, you will be able to specify the amount of Metal and Crystal you want to buy. You can ask for as much resources as the worth of your Deuterium and as the according storage can take. Definitely it will be profitable to upgrade the storages before trading, because every trade event costs the same, regardless of the amount. Because of that, a trade should be done on a planet, because there large storages make sense compared to a moon.
After you have entered all amounts, you only have to click on the button “Trade resources!” to confirm the trading event. After that, you get the designated resources, and the trader will receive the exchanged resources and disappear.