To buy a virtual phone number in South Dakota with Dialics, you need to register an account. After the registration, users have a seven-day free trial period to test the functionality. During the trial period, only one phone number can be purchased. When the trial period expires, you can purchase any number of virtual phone numbers. However, you should confirm your credit card details in the account and have a sum of money on the balance to be able to pay for the minutes of calls.