There are quite a few very reputable journals (i.e. PLOS) which charge for publication. Conferences also charge, but the justification is that you get to go to

There are quite a few very reputable journals (i.e. PLOS) which charge for publication. Conferences also charge, but the justification is that you get to go to the conference! The test for me is : is this for profit? The "proper" conferences and the "free to access" journals are (should be) non-profit or run by a not-for-profit foundation, money has to come from somewhere to keep these afloat, but so long as there is no one cashing in then I think you are good to pay.