In UO Extinction you can create vendors to be placed in your home and vendors to be put in the public Skara Brae Market.
To place NPC vendors in your home you have to buy A Contract of Employment (1252 gold point) from a banker, double click it and then place it in a point of your home. The home must be "Public". If the home is set as "Private" you can't place a vendor NPC.
To place a vendor in the Skara Brae Market, go there and speak to Taylor The Mall Manager and buy "A Public Vendor Contract Of Employment", it costs 50000 gold point. Consider that the Skara Brae Market is advertised on all moongates of Sosaria!
Another news in our shard is that you have no tax to pay to the NPC vendors.
You will pay to the NPC vendor a 10% of the entire price of an item only if and when the item is sold.
Amazing, isn't it?