Economics and the samurai clans are a tricky subject. It is not honorable to conduct monetary transactions or to own too much – it is expected that if you are a samurai, your daimyo will supply you with all you need and if you are a daimyo, the Emperor will do the same for you. In reality, money is always needed and creature comforts are always desired. The Emperor can always demand much more than he needs, just to take wealth (and power) out of the hands of the clans.
Clans support themselves by many means. Growing food is the most honorable thing for a peasant to do and trading food is about the only honorable mercantile effort in the Empire. Jade is the most pure ore and used in many shugenja purification rituals; thus, supplying it to the shugenja of other clans is honorable.
Other supplies, like wood, metals, textiles and dyes, serve the samurai clans only as a source of income. Since actually trading is dishonorable, clans get around this by sponsoring a merchant family or families to caravan their commodities and haggle. Merchant families can thus gain a lot of money and status, which creates an anomaly in the Celestial Order. Merchants are very low in the Celestial Order and having that much power irks the more rigid people of the Empire. It can thus be very dangerous to be a merchant. Your life is at the hands of people you make powerful but also really don’t like you.