What the Trader can produce depends on his/her post count, but it will be limited by the daily allowance (stronger items cost more to the Trader in terms of this). Some items may also have other requirements, such as the Trader only being able to produce one ever (however all requirements will be Trader-specific, this just gives items some rarity). There will be a lot of items, some with effects, that will almost suddenly become available within the next few days. Just stay tuned so you can be on top of it when the chance comes to get equipped.
