Ryan Air will never ever do anything for free! Not even the change from K to C (as in the name Kiaran to Ciaran). Had recently that experíence, one of the many reasons I'll never ever fly with Ryan Air again - well, only if I don't have a choice... but usually I have.
Ryan Air is a low fair airline for a reason: you have to pay for every detail. The fabulous fares usually turn out with a lot of additions. So if flying with an Irish airline try Aer Lingus. And no, I don't have any business or personal connections with Aer Lingus, just my experience.
On another notion: getting names and spellings right is a must in the global paranoia and money making attitude anyways ...
20

carraig
21

krazykatie
If you are changing an initial then it could potentially be a different personaly flying so they won't do that for free, if it is a full name and just a minor spelling they will often do it free or at a minimal admin fee, I have done this dozens of times, occasionally thepeson youspeak to is having a bad day and won't do it,just hang up and try again.
Pro tip