I've come across many music producing studio setups that look absolutely amazing. In comparison, mine is quite small. Here's a little information about the kit I use for music composition and producing.
First off, I'm on a 15-inch 2018 touch bar macbook pro. Specs include: 2.6 GHz Intel Core i7
16GB 2400 MHz DDR4
Radeon Pro 560X 4GB + Intel UHD Graphics 630 1536MB
For those of you that know your macs, you'll notice this is the default setup for a 2018 touch bar macbook pro. I believe I paid £2,500 for it at the time.
Software-wise, I mainly use Logic Pro X (£199.99), occasionally booting up Pro Tools (£499 or £30 a month) for video sync work. Within these, I use Celemony's Melodyne (roughly £640 for 'Studio' version or £230 for the 'Assistant' version I use) to manipulate recorded vocals and instrumental parts; cleaning up tuning, changing pitches altogether, and sometimes adding in extra harmony.
For the synthesized instruments, I have - Sonic Academy's A.N.A (£49); Native Instrument's Action Strings (£269), Damage (£269), Reaktor (£179), and Absynth (£129); and a subscription to EastWest's Composer Cloud (roughly £20 a month), which includes Hollywood and Symphonic orchestra packages as well as solo ones; ethnic instrument packages; pop instrument packages, and synthesized effects (separately worth a lot more. For example, each of the Hollywood sections - Brass, Wind, Strings, Percussion, are all roughly £240 each).
For final bounces, I use Platinum Notes (roughly £75), a DJ app for balancing volumes to a default, which I like to do for all my works.
For keyboard input, I still use an old M-Audio Radium 49 4-octave controller (I paid £100 back in 2014), which needed a bit of driver tweaking to run with the new macbook pro and Logic version.
The microphones I have include - a Shure SM58 (£99) for live performances; two Rode NT5's for stereo work (£250 for the pair), and a Blue Spark Digital (I paid £260) for my studio recording. Once plugged in, the first two of these connect through a Focusrite Scarlett 2i2 interface (£155), while the Digital is USB powered.
What you use to listen back to your music is just as important as the technology you're using to create them. In my case, I use AKG K701 open-back reference headphones (£150). These have a great dynamic balance, making them perfect for mixing. When it comes to mastering, I'm using various outputs, these headphones being one of them. Others include - TV speakers (an old Samsung plasma); a 120W soundbar (Majority Snowdon II); computer speakers (only about 60W with a small 40W subwoofer and two 20W speakers); regular earphones, wired or bluetooth (just be careful of the bass balance); CD and radio players with a jack input. Basically, I find it's a good idea to hear how my music sounds on most speaker devices. That way, I'm able to find a neutral master balance that works for all of them.
As I mentioned at the start, this is a small setup, but over the years of building it up I've probably spent between £5500 - £6000. Obviously, you can wait for sales or find cheaper alternatives but I've been happy with every one of these purchases. That price doesn't include my real instruments (saxophone, clarinet, etc.), which would bump it up to the £10K mark. When you think about the big AAA composers, their setups are easily worth hundreds of thousands of pounds. I will inevitably build my collection but I highly doubt it will get to that extent. In order to fit it all in, I'd need a bigger studio... in a bigger house!