With the Shopify POS and Bloom, there are multiple different ways to give discounts to your customers. From member discounts through Bloom to custom discount codes in Shopify the POS system can handle any discount situation. 

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• Order level discounts 0:30

• Line item discounts 1:35

• Clearing discounts 2:40

• Discount tiles 3:05

• Membership discounts 5:45 

For more information please take a look at Shopify's support articles 

• Discount Management