How to create shop using villager egg:

At first you have to buy Villager Spawn Egg from vendor on spawn (or find egg in treasure chest).
Every player with Villager egg can have shop in trading area Bazaar or Riverside for free up to 16×16 blocks.
You have to place chest (storage for your shop) or double chest, chest doesn’t have to be too close to vendor place (chest can be under floor or behind the wall).
With egg in hand you need right click on chest.
You can select shop type by right/left clicking in air with egg.
You can select mob type of vendor by SHIFT + RIGHT clicking in air.
After selecting vendor type and mob type, right click on place, where should stand.
Vendor can’t be moved, so be careful.

Placed vendor can be configured by SHIFT + RIGHT click, after this shop GUI will show. You place what are you selling in 1st line, price in second/third line.
Video tutorial here: VIDEO

Shop rules:

Every player can have unlimited amount of vendors, but only one free shop in Bazaar or Riverside up to 16×16 blocks.
Shop size can be extended for 1 diamond block per line (17×17 will be for 2 diamond blocks).
Payment is accepted by admin team. Diamond block will be used in future as reward in event(s).