As the name suggests, Wholesale Club by the developer Orbit enables you to set wholesale pricing for your products instead of creating a separate store for wholesaling. The is minimal yet comes with advanced features like account tagging that allows you to offer wholesale prices to certain customers. Furthermore, you can set order minimums, volume discounts, custom pricing, and control product visibility. 

Best of all, the app is free for Shopify Partners and development stores. Paid pricing starts from $39 per month with a 30-day free trial.