Both those options are expensive.
Are you handy at all?
You can probably change the whole ign switch and get 2 new keys with it in about 15 min. They are only like $25-40, way cheaper than a locksmith or getting a dealer involved.
And really, most boat igns suck. YOu can cram just about any key you arent' fond of in there for temp purposes. Mail keys work especially well.