If your product is a SaaS subscription, you need to offer a free trial by default if you want to succeed. However, you also have the option of requiring users to enter their credit card details before the trial starts. This will reduce signups significantly, but it will increase the quality of those who do sign up. People who enter their card details before trial are showing serious intent and are therefore more qualified leads than otherwise. This method can be ideal for smaller companies who don't have resources to handle large quantities of freemium users.