They turn out to cost more than they originally seemed to.
I think the above sentence is in passive voice, though it does not follow the rules which the other passive constructions follow, i.e there is no subject followed by auxiliary verb and past participle form of verbs. I think, they originally seemed means other people thought that they would have cost less than they actually did. Am I right? Please name the list of verbs that express the idea/thinking/feelings in the way passive construction of a sentence expresses. It seems to me that turn out is also such kind of verb which works in the way passive construction works. Please correct me if I'm wrong.
I would appreciate it if anybody suggest me a better way of rewriting the sentences which I have written above to explain my query, if he/she think that my sentences are awkward, unnatural, and they should be improved.