3. (!) We have so called 'short' forms of adjectives. "Бесплатна", "напечатан", "красив" (vs. "красивый"). This forms in general take function of "is + full-form". Bun not all of them are equally possible! "Бесплатна" (for my ear) sounds slightly better than "бесплатен"(NB!), "красен" "зелен" "чёрен" are rare/archaic, while in contrary 'красив' is used more often than 'красива'. But when one uses the full-form of a word, those who listen might wait for continuation: "Он красивый...."->***aren't you going to say "он красивый человек"? *** So 'он бесплатен' just sounds less great itsels (see NB! above), 'он бесплатный' sucks for other reason and the guy choses formal 'он является бесплатным', which 4)) fits to pretty official anouncement he gives.