Paul

You may choose a colourful style for the custom coupon message, or wrap the message in your own CSS class container.
It’s also possible to hide the default message from Woocommerce so that only your custom coupon message is displayed. 
(the plugin uses inline CSS to hide the default Woocommerce message).
Take a look at the screenshots for the coupon edit screen with the plugin enabled and some examples.
The meta box was implemented using the technique described on this blog post: 
http://wp.smashingmagazine.com/2011/10/04/create-custom-post-meta-boxes-wordpress/
The message styles were generated using this tool: 
http://www.bestcssbuttongenerator.com/

Woocommerce Custom Coupon Message

This plugin adds a meta box to the coupon edit screen where you can make your own customized coupon message.

PrecisionWP

Discount Master for WooCommerce is a comprehensive WooCommerce Dynamic Pricing and Discounts plugin designed to help you implement various discount types, including bulk discounts, quantity discounts, product-specific discounts, dynamic pricing, advanced discounts, percentage discounts, and tiered discounts. Easily create and offer quantity-based discounts, volume discounts, cart-based discounts, and discounts based on total order value.
Features
<ul>
<li>
Percentage Discounts: Offer store-wide percentage discounts or apply them to specific products or categories.
</li>
<li>
Bulk Discounts: Set up volume or quantity-based discounts to encourage larger purchases.
</li>
<li>
Cart-Based Discounts: Provide discounts based on cart total, item quantity, or specific products in the cart.
</li>
<li>
Product-Specific Discounts: Assign unique discounts to individual products or variations.
</li>
<li>
Category Discounts: Apply discounts to entire product categories to promote specific collections.
</li>
<li>
BOGO Deals: Create “Buy One Get One” offers to incentivize additional purchases.
</li>
<li>
User Role-Based Discounts: Customize pricing for different user roles, such as wholesale customers or subscribers.
</li>
<li>
Scheduled Discounts: Plan promotions in advance by setting start and end dates for discounts.
</li>
<li>
Exclusion Rules: Exclude specific products or categories from discount rules as needed.
</li>
</ul>
Highlighted Discount Types
<ul>
<li>
Storewide Percentage Discount: Implement a universal discount across all products. 
Example: A 10% discount on all items during a holiday sale.
</li>
<li>
Bulk Purchase Discount: Encourage larger orders by offering tiered discounts based on quantity. 
Example: Buy 3-5 items for a 5% discount; 6-10 items for a 10% discount.
</li>
<li>
Cart Total Discount: Reward customers who reach a certain cart value with a discount. 
Example: Spend over $200 and receive a 15% discount.
</li>
<li>
Product-Specific Discount: Apply discounts to particular products to boost their sales. 
Example: Get a 20% discount on Product X for a limited time.
</li>
<li>
Category Discount: Offer discounts on entire product categories. 
Example: All items in the “Winter Collection” category are 25% off.
</li>
<li>
BOGO (Buy One Get One) Offers: Encourage additional purchases with BOGO deals. 
Example: Buy one T-shirt and get the second one at 50% off.
</li>
<li>
User Role-Based Pricing: Provide special pricing for specific user groups. 
Example: Wholesale customers receive a 30% discount on all products.
</li>
<li>
First Order Discount: Attract new customers by offering a discount on their first purchase. 
Example: New users get a 10% discount on their first order.
</li>
</ul>
Benefits
<ul>
<li>
Increase Sales: Strategically designed discounts can boost purchase quantities and overall sales.
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<li>
Enhance Customer Loyalty: Personalized discounts for specific user roles encourage repeat business.
</li>
<li>
Flexible Promotions: Schedule discounts to align with marketing campaigns and seasonal sales.
</li>
<li>
Easy Management: User-friendly interface allows for effortless creation and management of discount rules.
</li>
</ul>
Compatibility
Discount Master for WooCommerce integrates seamlessly with WooCommerce and is compatible with various themes and plugins, ensuring a smooth experience for both store administrators and customers.

Discount Master for WooCommerce

Discount Master for WooCommerce is a powerful plugin for dynamic pricing and multiple discount types in WooCommerce.

Woocommerce Custom Coupon Message vs Discount Master for WooCommerce