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". ^___^