How can I convert an AI file to a CDR file? Assume I have an AI file, Adobe Illustrator CS 5 and no CorelDraw. How can I convert this AI file to CDR file? What is the fastest and cheapiest way?
What version of CorelDRAW? What's the workflow? 

.CDR is a proprietary format, so I'm not aware of any proper supported exporters. The sK1 project reverse-engineered the format, and claims to have the best support. But since recent versions of CorelDRAW can import Adobe Illustrator CS4 files, I think you would get the best results to just save it as .ai and import it into CorelDRAW.