If you want to give your clients a first year for free or 100% off one time or recurring you can use this module. It will not ask users for their Card Information like other gateways even if the invoice amount is 0. You can also use this gateway to provide FREE first month/year of any product. All you have to do is make 100% OFF promo code for that particular product and make sure you set it up for once per client.

Be advised that clients have to enter the Promo Code that is 100% OFF or equals to the value of the product. Create a Promo Code Wisely in WHMCS Promotions.