They're called 'trade journals' these days, and many of them are actually very good. Articles are usually by invitation only, and case reports are usually not a part of them. Your best bet would be to submit to peer review journals in your subspecialty that accepts case reports. There's no 'easy' case report though imo, and there's an art to writing them. The legit journals should have a good review process and the "simple journals" as you mention would probably be the open access ones but they come with a publication fee, some lower than others.
