Way back when, I seriously considered building a Bahama Mama. It's a cool boat.
It's a pretty simple build and, at a cost of somewhere around $50K, it's a a lot of boat for the money as such things go.
Of course an older, classic plastic boat like a CAL 29 (this one for sale is a good example) pretty much ready to go would only cost you 20% of that...
Something to think about.
Sadly, these days, building a boat is really no longer a way to save money so, you have to ask yourself if the great pleasure and satisfaction of building your own boat from the keel up is worth the price.