I'm another youngster who's been at this in a 30 foot boat for a year. There is great truth in the statement that a dorm room is training for a liveaboard. Anyway here are some points of consideration.
you could get a boat on ebay or craigslist.
don't know what it is where you are, but around here a survey is $20 a foot. for a good survey you gotta haul the boat out to see the bottom and splash it for a sea trial, so you need to account for a haul n launch.
To get a 30 foot boat inspected, for me, cost $1000 because the previous owner wouldnt come and insisted i hire a captain for the sea trial.
After that, you're making repairs to get the boat in liveable conditon. Oftentimes, the windows are leaky and need caulking (or butyl tape if you don't like to redo it every year), the ac wiring is insufficient to carry a space heater, the plumbing may need something.
All these first time expenses point to the necessity to get a loan for the boat purchase.
After that, there's regular maintenance. Sanding and painting the bottom is expensive and filthy, and even more expensive to have it done. Engines cost money to maintain, unless you're mechanically inclined.
You can get insurance from boatus for not much. I recommend towing insurance if you go sailing, tows are ridiculously expensive.
Points of consideration when looking at boats
-Does it have a head? How big is the holding tank?
-Does it have a fridge? These are valuable!!
-Does it have a shower and hot water?
-Can you stand up in it?
-If you run a space heater, will it trip the breaker? Will it burn up the shore power cord?