This is great marketing module for PrestaShop that creates special section on your Facebook Fanpage with feature to receive unique dedicated voucher code for each user who will like your fanpage. With this addon you can specify each aspect of coupon code.
more informations about this addon you can find here:
Coupons for Facebook fans
You can find there only valuable solutions for your e-commerce shop based on PrestaShop engine. Search the best plugin for your store that will meet your requirements and just use it.