Rares on Habboon are hard-to-get, expensive items that are worth a lot to collectors or people who like to make high profits.
Sometimes rares get very expensive so people can't keep track of what the cost of their rares are in coins so people trade rares with Thrones. One throne is worth 25,000 to 50,000 coins. Trading rares for rares is very hard because most rares are all different prices. A lot of rares are paid with thrones as throne is considered a secondary currency, then following credits.
To make money by selling rares, simply buy rares from catalogue for cheap. Then you wait a while for your rares get more valuable. You can then sell them for a price higher than what you bought it for.