There are purists that argue that if you are a 'real writer', all you need is a pen and some paper. Maybe a few pens. The quantity of pens and paper is dependent on the length of your writing endeavour and your affection for rewrites. I think we should take it a step further. I believe that if you are a real writer, then all you need is your mind.
A real writer is engaged with the process of the art, and remains entirely apathetic to the final product. After all, if we were at all concerned with the final product we would make movies, the worst of which is a lot better than any book could ever be. The trick is in convincing others that they should pay for the book that you have written in your head. There are two obstacles that you will need to overcome. The first being whether or not you have actually written the book, and the second being the quality of the book. Both of these hurdles are easily circumvented through the liberal application of hypnotism. Hypnotism can also be used in a variety of non-literary scenarios, and I recommended it as a skill to be cultivated regardless of your intent to become a writer.
If you are in fact more concerned with putting actual words together into a final product that others are able to participate in without the use of mind reading, then an exclusive pen and paper set up may not be the way to go. You will probably need a variety of tools. Some different coloured pens, maybe some pads, a typewriter is fun, desktops are useful, laptops are better, and software is awesome.
There is a lot to cover here. I mean, the tools and arrangements that will change your life, are not counted upon a single hand, outstretched or otherwise. It is about being prepared, and making sure that you are prepared to operate in any given scenario. You will be like a Batman of words, except your stuff is not going to fit into a utility belt.
If you want a single tool to solve all of your problems, then I am going to disappoint you quite extensively, repeatedly, and probably on a number of levels. Unless you are doing only one very specific type of writing, then you are going to need some toys as opposed to one toy.
To absolutely contradict myself I am going to say that the one tool you really want is a laptop. This is the best case scenario. You can write pretty much wherever you need, or happen, to be. You can take it to interviews, or meetings, or the library for research, or cafes, or my mum's house. Well, not my mum. Your mum. Unless you know my mum, and she wants you to visit.
That said, there are ergonomic and productivity concerns with laptops. They aren't really good for you as a primary writing implement, because laptops on their own are basically RSI and neck pain machines. Then the screen space available is also going to drive you up the wall when you are in big edit mode. Fortunately you can get a monitor, keyboard, and mouse for your laptop and treat it as a desktop when you are at home.
The ideal scenario is a MacBook Pro or Air, and a Thunderbolt display with appropriate peripherals, because they have been designed as docking stations for your mobile life. But, starting at just under AUS$2,500 this isn't within everyone's price range. That is also before you start buying any software. So, how do poor, struggling writers get them some tools of the trade? And what tools should we look for?
The four 'F's of acquisition. Friends, family, found, and Freecycle (and similar services). If someone is throwing out a laptop, or has one sitting in a cupboard that they don't use, they might be willing to pass it on. Word processing is, generally speaking, not a hugely taxing activity for a computer. It can be, but that is usually when formatting and tracking changes, or poor memory handling if you happen to own some versions of Microsoft Word for Mac. If it is portable, and it works, it'll do. I've even part-timed a laptop in the past in order to get some writing done.
Monitors can be similarly acquired, but you will need to make sure that they are compatible with whatever display port your laptop has. There are a few different types of display port, and
it is worth knowing what you have because you might need an adaptor, or preferably a converter cable (has a different port type on either end). Converter cables I find stay plugged in more securely, which is a plus for something that is getting plugged in and unplugged on a regular basis, and they're also, quite bizarrely, cheaper.
A mouse and keyboard will set you back maybe $10-$15 dollars depending on where you shop, but they are again something that people tend to have lying around, and may be willing to part with.
If you have some money, and don't really want a bunch of second hand computer stuff, which can be a valid concern, a new low end laptop, monitor, keyboard, and mouse can be picked up for as little as A$550, but this is also highly dependant on where you shop.
The one laptop accessory I think that everyone should own is one of those padded lap table things. They're pretty awesome even if you don't own a laptop. So many uses. I have no idea what they're called. They're called lap desks. I just googled it. Google wins again. So, lap desks are amazing. I'm not really sure how ergonomic they are, but they are fantastic for sitting the wrong way on a sofa, or in bed, in the garden, on the floor, or pretty much wherever really. I use mine a lot. A lot, a lot. Especially when I'm editing. You can get them around the place for a relatively small amount of money. I've seen them as cheap as $7, but
the one I have was $15.
There are more parts to this, because the original draft got crazy long. About four times longer. You're not going to read all of that. Not in one go. There is a good chance you didn't even make it this far. But, when I post the other bits I will cover backing up all of your writing, as well as some software that will probably change your life. That might happen a few times. The software, not the life changing.