My No 4 plane was bought for $20 or less at a road side junk sale. No brand name on it, thin blade, but I do a hell of a lot of good work with her ... once I'd worked out how to get her sharp. My Dad's good Stanley 4 1/2 hardley ever comes out of her box.
The low angle block plane is a great weapon and will do most of what you want. I bought the Stanley with the non-adjustable mouth.
Buy your low angle block plane first and keep your eyes open for a half reasonable No 4 second hand while you save for a new one - my bet is you won't get the new one because you'll find a good second hand one first.
Don't fret about buying a cheap plane - like the chisel (see later), they'll do a lot of cleaning up of old epoxy and while you can use a good plane for that job, it's nice to have a cheapie to do it - your cheap plane will always have a place in the shed.
Power saws - get a jigsaw that plugs into a power point (and an extension cord). That will do everything you want when building a boat. Mine's a Ryobi and that's plenty good enough. Try to find some 'plywood' blades for it, they make a much nicer cut (slightly finer teeth and a narrower blade). The other saws will do some things better but your jigsaw is the only one that will have a crack at everything.
Buy a Black and Decker Mouse Sander. Cheap, horrid little brutes that do a tremendous amount of damage to irrascible timber and epoxy and last forever - they also fit into some really silly little places. I've tried and looked at other detail sanders but for me, the Mouse is the choice if you've only got one choice. Later, you'll appreciate a real random orbital sander but it's only usefull for open, flat surfaces - buy one when you can afford it and when you need it.
Get a cheap, 1" chisel ... and learn to sharpen it. There isn't a lot of fine joinery in a boat but a lot of cleaning up of epoxy ... which is why cheap is good. You can also hold them vertically to the surface to scrape off pencil marks and epoxy ... which is also why cheap is good. There'll always be a place for a chisel you don't care about (week old poxy springs to mind) so this is one purchase that will never be wasted, even if you buy a good set of chisels.
I bought a cheap, wooden mallet which gets used all the time and which drives me nuts because it's cheap and the head won't stay on the handle but it still does the job and is a better choice for whacking things (not just chisels) than a steel headed hammer. If I'd bought a really good one, I wouldn't be as frustrated as I am and because it keeps doing the job, I'll probably never buy the good one :doh: But just get cheap to start with unless someone wants to give you a present.
A cordless power drill is damned near a must have and you'll use it so much it's worth buying the best you can afford ... with two batteries.
A knife with snap off blades is darned useful and a good present from kids or rellies.
Each one of those purchases will be replaced/upgraded as you get more money and experience however, everyone one of those will continue to have a use as you get better machinery. They're also the heavy day-to-day use weapons so they're a pretty good start.
Richard