Within your CRM there is a transaction screen, as well as subscription management. Using these tools, you can establish subscriptions on an individual basis This means, each subscription that you establish can have its own price and term length.

First, establish a primary payment method for the customer. (Read more here)

Next, create the initial payment as a "one-off" transaction using the Transactions module. (Read more here)

Last, create the recurring subscription to the term and price desired. (Read more here)