Deciding to become a musician is a huge step in your career. But deciding it is only the first step. There's so much that goes into it, and you're not going to start right away. There's a lot of preparation involved. But that shouldn't scare you away from wanting to pursue your dreams.
A great place to start is your gear. You don't need everything all at once, but a little bit goes a long way. You want to be a trumpet player? You don't need a Bach Strad. You want to be a composer? You don't need an iMac. You want to play the guitar? You don't need a bunch of fancy amps and pedals. Sure, it would be great to get a lot of these nice, expensive things somewhere down the road. But what you need to remember is that having a lot of cool stuff, industry-standard software, a $3,000 trumpet, or a home recording studio does not make you good at what you do. It's the knowledge and experience that will go a long way.
For the purposes of this post, I am going to go into detail about what you need as a music composer and producer in the modern world, and then what stuff you should get at some point, because it's not all going to happen at once.
Start with the basics.
Ask yourself, what do I need first? Think of a home studio, and think of all the things you would expect from it. A computer, speakers, headphones, a keyboard, microphones, etc. Now at this stage, I wouldn't say you need to get everything all at once. When I say start with the basics, I mean the basics.
Now I assume that since you're reading this post on my website, you have a computer of some sort. Perhaps it's a phone, but if you have a laptop or desktop, doesn't matter what operating system it's running (Windows or Mac), you're golden. That's step one. I started out with an HP Windows 8 laptop, and since then, I've moved up to a MacBook Pro. On this laptop, you're going to be doing some basic audio work.
The next step is a DAW. If you plan on working with MIDI or audio, a DAW is a must have. If you want to just do some basic audio editing for free, I'd suggest Audacity. Other than that, you're going to have to pay. Unless you already have a Mac, of course. Included with Macs is a great entry-level software called Garageband. If you're looking to upgrade to something a bit more professional, however, Apple makes a much higher-quality version of Garageband that I personally believe is everything you could want from a DAW. It's called Logic, it's Mac only, and it's what I use. For $200, it's a price you can't beat, ESPECIALLY considering the amount of samples, stock plugins, and loops you get with your purchase. Besides that, there are several other industry standards that work for both Windows and Mac such as Cubase, Pro Tools, Ableton Live, and Digital Performer. They are all extremely expensive and I would not recommend them if you are just starting out. There are some lesser-known ones that I would recommend for beginners that are pretty cheap. Among these is Reaper.
Some other software you should be on the lookout for is notation software. This is what you will use to write out sheet music. The industry standards are Finale and Sibelius, though there are free ones out there too that I would recommend for beginners such as Noteflight, which is online, and Musescore, which is a downloadable program like Finale and Sibelius. I personally am an advocate for Finale, although many of my colleagues swear by Sibelius.
Now we return to hardware. The most important thing you will need (in my opinion) for use with your DAW is a MIDI Controller, or MIDI keyboard. these are piano-style keyboards that can send MIDI data to your computer and your DAW. You can get small ones for cheap (around $60-$70) from some websites. I personally would recommend buying a larger keyboard (not full size) for around $200-$300. The one I use is a Yamaha PSR-E403 which has 61 keys.
Besides that, I'd say get a decent pair of headphones. You can always upgrade later. I would say invest in a nice pair of cans, and if you invest in the right pair, they will last you a while. I use Sony's MDR-7506 and AKG's K240 Studio. Speakers are an investment at some point, but if you can't afford it right now, wait. Don't go out and buy what's cheap. Do some research and save up for some nice ones.
Things to get down the road.
First of all, I'm going to recommend you switch to a Mac at some point. I swear, for audio, Apple is lightyears ahead of Microsoft. I am currently saving up for an iMac. When I get it, I plan on upgrading its RAM to 40 gb so I can run some sample libraries with less latency.
Probably the most important thing you should do on this list, probably the first thing you should do is BACK UP YOUR STUFF. Get some external hard drives, or even internal ones. My studio comp professor at Purchase College, Silas Brown, drilled this into our heads. His rule is that if you have your work on one hard drive, it doesn't exist. If you have it on two, it exists. If you have it on three, NOW it's backed up. I would suggest getting a hard drive dock, which is for plugging internal hard drives into your computer. You can then use that one dock, and get several internal hard drives at a decent price. Remember, if you can afford SSD's (Solid State Drives) you should use those. They're less likely to break, and they are faster. If you can't (I certainly can't) then I would recommend 7200 rpm internal hard drives. Get a few so you can back up to multiple drives. Remember, the money you save by not backing up your stuff is meaningless if you permanently lose everything.
I'm not going to go into too much detail for the next stuff, but know that sometime you should get an audio interface, some really good sample libraries (Kontakt, EastWest, Spitfire, Vienna, etc.) and some microphones.
Remember!
No matter the level of equipment that you have, there's nothing preventing you from being the musician you want to be. We all start somewhere, and we all take different path. Start out small, and you'll be surprised where it takes you!
Here's a few websites to get gear. Some of these offer some really great deals and sales if you're patient.
https://www.sweetwater.com/
https://reverb.com/
https://www.musiciansfriend.com/
https://www.newegg.com/
https://samashmusic.com/
https://www.guitarcenter.com/