Adding extra's after you have booked your flight

I think I remember seeing something about this on here before, but currently unable to find it at the moment, from the News section...

Passengers wishing to change their dates of travel or add services to their booking, can do so at significantly cheaper prices by clicking on the following link:
https://www.bookryanair.com/SkySales/FRManageBooking.aspx?culture=EN-GB&pos=MYFLIGHT
The following services are available to be booked online:

• Change travel dates of your party
  
• You can also add any of the following to your booking:
  
  
  
• Priority boarding
  
• Checked bags
  
• Sports equipment
  
• Musical instruments
  
• Baby car/booster seats
  
• Travel Cots
  

Via this link you can also review and print your flight details and services already purchased.

Now I haven't gone into it, to see the prices they are charging, but anything has to be better than calling Ryanair's premium rate phone lines.