I need to renew mine.  When I bought my 2nd canoe in 2006 it was $13 for a Transfer and Renewal.  The previous owner had let the registration expire.  My other canoe registration is due this year, oops at the end of June 2008.  I believe it is $5.00 for 3 years.  If you think that you might remotely put a motor on the canoe, mark that on the registration.  It did not cost me any additional to mark it as outboard powered.  I put 6hp.  I have heard that if you don't mark it as an outboard the DNR police can give you a citation.  I have never had any experience with that at all.  Good luck.  River levels are down around my part of the state right now.  The Mackinaw River is at the lowest I have seen for quite a while.