From brc plugins wiki
By buying this plugin you agree to the following rules:
- No refunds
- You may not redistribute the plugin or any part of it
- We may refuse to give you support without any specific reason
- You may modify the plugin for personal use only
You need a SpigotMC account and PayPal to purchase the plugin. You can purchase it here: purchase ShopGUI+. After purchasing you will be granted access to download it.