I once heard of a ranch named the Last Dollar
after what the owners spent on it. I always thought that seemed just as appropriate for a boat.
If you want to know what's popular, try here for a list of names to use (or avoid, if you prefer to buck the trends):
Here's a few other ideas, depending on your mood.
Feeling mythic, try Proteus
Bi-lingual: Velero Costoso
Regional: L'Étoile du Nord
And of course, if you happen to own a Yawl, the possible puns are endless.