Battler’s Connection has everything you need to build a ship, hulls, guns, motors, pumps, props. Some of the stuff we use you can make yourself, like the decks, rudders, for less money. We can make some guns at our up coming PPB gun building party in Jan or Feb for the cost of the materials $25-$30, last time I bought them. You can get hulls from:
BC http://www.battlersconnection.com
Artwerks http://www.rc-artwerks.com
The Canadian guys http://www.nabsrccombat.ca/
The Australian guys http://www.ausbg.org/BSY/#Order
From members who might be selling them http://www.mwci.org/forsale.shtml
BC has everything and sends stuff out the fastest.
Artwerks is just starting and Clark just got over some illness so he may not have everything ready right away.
The Canadian guys seam to be slow to ship things. One of them just got back from Africa. They do make nice thick hulls.
I've never got a hull from Australia but have seen a few. They look good but shipping might take a little longer and cost a lot more. See the attached list of different hulls that are for sale at the different places.
There is also Steve Millholand, who had Swampworks. He just took orders for hulls a few weeks ago so you might have missed the chance to buy from him. He is semi retired and only takes order once a year.
Now that you know where to get it what should you get? 
If you have never done any RC you should start with a cruiser (Class 2 or 3), even if you have lots of money and time. They typically get two guns and a pump. They are fast so you can run from trouble. Stern gun tactics are easy to learn. They are not overly complicated to build.
If you have done some RC stuff maybe start with a battlecruiser (Class 4 or 5). Most have three guns and a pump. They get to have sidemounted guns. These are harder to learn how to use but you don't sink other ships with stern guns only. They are a little more complicated to build. You will get shot up the first year or two until you learn how to hit people with your guns. A VDT is a great class 4 ship. Good gun set up, low in the water so there's not a lot of area to shoot at. Turns well. But it is slow (26 sec). A Lion has an advanced gun set up (Two bow sidemounts), does not turn that well, but is fast (24 sec). A Scharnhorst has trip stern guns and one bow sidemount, a lot easier set up to learn. It is fast, does not turn that well. It's more like a cruiser then anything else.
In rare cases, if you have done enough RC stuff and are very mechanical and electrically talented you could start with a class 5 or 6 battleship. The QE (I have one) is a great ship, lots of fire power, turns great, but is slow (26sec). The South Dakota also has lots of fire power and turns well but is also slow. The Nagato and North Carolina are both fast ships (24 sec) that turn well and have lots of guns. But even if you build them correctly when you first start you are going to get shot up until you learn the gun skills you need to fight them correctly.
No one should ever build an Iowa or Yamato. You can put Vanguard up there too. They are BFTs (Big Floating Targets). Lots of area to shoot at hard to start and stop, not great turning and they are heavy. Hauling one around gets to be the biggest pain (In your back).

Ask yourself this:
Can you cut things in a straight line?
Are you a good wood worker?
Do you know how to solder plumbing pipes together?
Can you solder electrical wiring together?
Do you know what NO NC C listed on a switch means?
What is pretinning?
Can you drive a RC car, plain or boat around an opsticle course without running into stuff? 

The more you can answer Yes to the higher unit ship you can get.

How much do you want to spend? More battle units cost more. A class 3 will be around $800. Class 6 will be $1000 to $1200. That includes everything from the hull to guns, motors, batteries, radio & glues. If you already have a radio take $250 off of that. You'll also need tools, soldering iron, torch, drill, dremel. You'll wish you had a drill press, disk & belt sander...

 Some people totally forget the above reasons to get a ship. They want to pick one that looks nice or has some emotional value to it. I picked the USS Minneapolis for my first ship because of where I live and its history. Mike C. picked the St. Paul for the same kind of reasons. Had nothing to do with completive battling just though they'd be cool ships.

Stop a battle or building meeting if you can and we can show you some ships and help you pick one. We are always looking for more targets!!!