You can specify a minimum quantity for a product. When the user adds the product to the cart and if the number of wanted quantity was greater than the minimum you specific, the price of the product will change to what you want. That price can be a percent or a specific value. This is wholesale.
One more thing
The plugin using i18n, So you can translate it for your language. The plugin has been translated to Persian already.
このプラグインをダウンロードして、インストール型 WordPress のインストールに使用できます。