This article is aimed at new players to the SMP server. If you have played for at least a month, you probably already know what is said in this article.
Nearly every day, I see a new player saying "Selling diamonds at my /home for $500 each! Come quickly!" only to be flustered when nobody comes to buy them. If this is you, then there is something very important you should know. Everyone is able to earn 5 free diamonds each day. You can do this by voting. At some point, you've probably gotten a pop-up message while browsing the forums asking you to vote. If you click this message, you will be taken to the voting page. Enter your username, click vote, fill out the caption, then repeat for the next website. For every website you do this for, you will receive a free diamond ingame. Thus, you can get 5 free diamonds daily (every 12 hours on XtremeTop100; every 24 hours for the other 3 websites). Consequently, the price of diamonds has fallen tremendously.
But the market says diamonds are $750 each!
That's true, the market does say that. But the market prices are based on an item's natural value (in this case, how much diamonds would be worth if the only way to obtain them was by mining). The market does not account for earning diamonds by voting, otherwise the price would be about $50. You may notice that there is no sell sign for diamonds at the market. This is intentional: if you could make $2500 daily with no overhead, the server's economy would be skewed.
So how much are diamonds worth, then?
About $50. Even then, most people won't buy them unless they can't wait until they can vote again to have diamonds. That being said, using diamonds in trades is fruitless, as the person you are trading with most likely has stacks of them in a chest, which brings me to another point: always negotiate trades before giving anything. Several people have come to my shop wanting to buy something and threw their items in the "Give" channel without saying anything. After a minute of me doing nothing, they angrily demand the item. I usually sell items for money and not other items, so I tell them that they have not paid. They respond "Isn't what I gave you enough??" (Usually one of the given items is a diamond). I reply that I asked for a cash payment, and that I considered the items given to be a donation, since they did not ask if they could be used as payment, to which the answer would have been no. At this point, they usually storm out of the shop without even asking for their items back.
Everyone can receive 5 diamonds daily by voting. The average sell price of diamonds is $50. Always negotiate a trade before giving items.