A graflex is a good start. And it also happens to be a good use camera as it is quite portable and fairly easy to use. A graflex is around a few hundred bucks, I paid about $200 for my Pacemaker Speed Graphic. From experience, I would suggest a Pacemaker Crown with the top rangefinder.
I have a 135mm lens on mine and a 150mm on my sinar. On both, the lenses screw into a shutter which mounts to a lensboard. Lensboards are rarely compatible between cameras. They are usually compatible with various shutetr and lens combinations, as long as the shutter is the right size. On my graflex, the 135mm does not need to be dismounted for the camera to fold. My 150mm is not much bigger, but I have no interest in trying it.
Lenses, to start, if you can find a camera with one already included is the best start. Again, graflex cameras on the bay of e frequently have a lens included. Most all LF lenses are quite good. Even the older lenses made by places like kodak and who knows where are still quite good. Fujinon, sinaron, rodenstock, and new schneider lenses are really good. There are plenty of more brands, but I can't think of them all. Then of course, there are things like process camera lenses.
To start, a tripod is useful. I personally started with a borrowed graflex and shot handheld. You will need 4x5 film and some film holders. Avoid wood holders, go for newer metal or plastic ones.
My big tip is to buy a complete graflex set. They have a nice lens and shutter combination (usually) as well as wire frame, viewfinder, rangefinder, and ground glass focusing. They also have a folding piece in the back that works as a focus hood, negating the need for a dark cloth.
My big bit of advice is that you browse graflex.org and join their forum, as well as read the articles at largeformatphotography.info and join the forum there.
Basically, the stuff I mentioned gets covered in multiple articles and many books. There is a lot of info on what to choose and how to use it, as well as how to get the most out of it, it is simply amazing.
Also, I suggest picking up a copy of the book View Camera Technique. Get the newest edition you can.
Bets of luck.