Free trials are an excellent deal, but unfortunately, you cannot get a free trial without adding your credit card details. It is against the terms and conditions of Sling TV. You have to cancel the subscription before the free trial, or you will be charged as the company doesn't notify viewers about ending the free trial period. However, a virtual credit card works differently by providing a temporary credit card number to your Sling TV app. If you forget to cancel the subscription while using a free trial, then only a specific amount will be deducted from the virtual card that you have selected. This is how a virtual card works: It does not pay to any random credit card number It is approved by a free trial and billing system It prevents companies from charging you once the virtual card date has expired