I didn't worry about the event when I was on low rune, those things you will eventually have too much of. It's the medium and advance that really matters, which most people aren't done with for a long shot, so it's not too bad to begin saving for the event. Do note however, the event is useless if you only lv up the refinement one level, because the bonus is toward next level and will disappear, make sure you save up enough to at least get 3 level out of a gear (the entire medium tier, for example) which is around 200 before doing the refinement, possibly skipping some of the events.
I will stay F2P!!! I just leveled up 125-165 and i'm almost gonna up it to 210 now. Just need more and i will save after that :D