BRP offers support for handling automatic price changes and keeping track of promotional periods if you want to offer campaign subscriptions for your customers. Examples of campaigns that BRP can handle are:
Subscribe for 13 months, pay for 12 (first month for free)
Train until August 31st for €40, then €30 for one year, then regular price €50
Train cheaper for a year then regular price
Read more about how to set this up here.