You should wander the docks and talk to people and look at boats. That will teach you a lot, and help you figure out where you fit on the spectrum of (a) money, (b) liveaboard vs cruiser, (c) requirements for living space.
THere are no simple answers. Every decision involves a complicated trade-off.
Cruising (as opposed to living aboard) a motoryacht tends to be expensive -- the boats are pricey, and most of them use gobs of fuel under way.
Hence, most long-term _cruisers_ are on sailboats.
Liveaboards can go either way -- fuel costs aren't a major issue if the boat sits at the dock. And, per foot of length, most powerboats have much more interior room than most sailboats.
For sail training, anyplace on the coast will have a sailing school teaching ASA courses in "basic keelboat sailing" and/or "bareboat chartering". The US Power Squadrons have similar training for powerboats. That's where you should start.