Hello. The first two sentences are correct and could be used interchangeable. :) However, the last sentence is incorrect...if you want to say the last sentence, then this is better: "No matter what the cost is, I want to have it." If you change it, then yes, all 3 will be interchangeable. :) Hope it helps. **If you want to sound more natural or like a native-speaker, then instead of saying "want to", say "wanna". ^___^

Liya's answer is great, except I disagree on the 'wanna'. You can see the comment below, if you like.