Budget Travel - Easyjet - purchasing baggage online after ticket purchase?

Hello everyone. I wish to purchase an easyjet ticket for travel in june 2012 but have not yet decided if I will be travelling carryon only OR checking in a bag. I want to therefore purchase my ticket now online with no baggage allowance but want to be sure that I can go back at a later date (say 1 month before travel) and retrospectively purchase the baggage allowance. Is this possible and is it the same price as it would be if I purchased the baggage allowance at the time of purchasing the online ticket? Thanks.

Its so easy just make your booking now and you can always add bags later

thanks. I thought that would probably be the case but have never booked on EJ before.