"먹고 싶은 거 사 먹고 옷도 사 입고" => Buying and eating what I want to eat and clothing myself as well (literal) => Freely feeding and clothing myself as I wish - 먹고 싶은: that I want to eat (adjective phrase). ~고 싶다 (I want/like to ~) -> ~고 싶은 (that I want to ~). - 먹고 싶은 거: things(거) that I want to(싶은) eat(먹고) - a noun phrase. - 사 먹고: 사(서) 먹다 = buy(사다) and eat(먹다). ~고 is a connective ending for a light "and". - 옷도: 옷(clothes) + 도(particle for as well, too). - 사 입고: 사(서) 입다 = buy and wear. -고 ending means it is continuing on to the next part. * On #3 of your list, "은" is part of a verb conjugation of 싶다, and has nothing to do with the topic marker 은. * The subject is omitted in this phrase, but the previous line "내 돈으로 ..." makes it clear the subject is "I". * ~고 ... ~고 is like "Feeding myself AND clothing myself as I wish, AND knowing how to be content ..."

the thing that the person wants to eat "먹고 싶은 거 (것)" = things i want to eat