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.

Unreal Themes

Apply Coupons to Custom taxonomies using the Woo Coupons System. 
Discount type of Coupon must be the “Fixed cart discount”. 
Download the zip folder and upload it as normal WordPress Plugin. 
This plugin adds the ability to select one or multiple taxonomies including products categories, tags and custom taxonomies and applies the coupon

Woo Custom Taxonomies Coupons

Thanks @romchyk16 for this plugin. Like @abisewski I was unable to get this to work and have spent a couple of hours debugging it. Despite an invalid coupon being present for my custom taxonomy, it was still being applied. Why was this?

Well, the plugin runs on the woocommerce_coupon_is_valid_for_product filter. This was not being run because the coupon was set for a percentage or fixed cart discount. The filter that this plugin runs on only applies to a Fixed Product Discount.

So, please update the plugin with an instruction that the coupon 
Discount type needs to be Fixed Product Discount.

Thanks, all working now :)

Excellent plugin, needs more instructions

Apply Coupons to Custom taxonomies using the Woo Coupons System.

Woocommerce Custom Coupon Message vs Woo Custom Taxonomies Coupons