Martijn
I am still using MacGPG, I just find it easy to install and as of yet they are still free. Also: it is GPGMail they want to charge for, an unnecessary addition to the suite. A good guide I bumped into recently is this one:
notes.jerzygangi.c.... Interestingly that guide even recommends against installing GPGMail and sticking with the other tools. I have also stopped using GPGMail as it uses some attachment-based system that is not supported by K-9 on my phone.