Is there a way to run a BOGO and allow our preferred members to use a discount code to receive an extra 10% off ? I've been researching this topic and it appears that Shopify does not support discount stacking. I know you can't add two discount codes at checkout...but can you combine an automatic BOGO with a discount code? Our members always get 10% off...and it seems strange that they wouldn't be able to use their promo code during the BOGO event.
App Selly can help you to offer BOGO:
There is an option to enable discount box in cart, so customers can apply additional discount code together with other Selly automatic discounts.