I believe Brazilian comics have to have value like any other comic book I imagine. I suggest creating an account with http://comicspriceguide.com as well as looking at eBay prices then you have some idea to work with. I know there is a couple of others who have comic books listed, I believe the more the merrier, geeks use Bitcoin, geeks read comic books, I know this because I live it lol. OpenBazaar has only grown since I've been using it and it's only be out less than a year, so far so good.