Do you like to build computers and have some spare currency of some sort? Because if you do, you can set yourself up for, at the very least, a fun and self-sustaining hobby! It can sometimes be frustrating, and it will always be full of fan noise, but I will bet that GPU mining (using video cards to mine crypto) will be profitable for quite some time. Barring extremely bad legislation and/or complete corporate takeover, people with a couple grand to spare on a do-it-yourself project will be able to pay themselves back within a few months and then make enough to fund future projects and accumulate some crypto or cash out to local currency. Before you even think about doing any of this you should know how crypto works, and you should do some research into which coins have a great future ahead of them and which are the most profitable to mine. Ultimately you'll find a balance between both.
It's true, if you can build a computer and have a little time and money, there isn't a whole lot more you haven't done before to get it off the ground. You are going to get a motherboard with at least 6 PCIE slots and some RAM and an SSD of some sort (flash or SATA) and a CPU and some pcie risers and some video cards and a big honking PSU and some fans and some assorted accessories and some free time. You put those together, apply a few hours, and out comes a fully functional mining rig. There are a few things that may be new to you, but new things can be fun, and fun is good.
One thing you may not have heard before is "PCIE risers". We want to get the video cards up away from the motherboard so we can manage the heat from the cards and keep things cool. So you get a riser and use a USB cable to connect the PCIE slot on the board to another PCIE slot that you plug into a card that's mounted a few inches to a foot above the motherboard. If you run more than 4 cards off of one motherboard, you will need to make a tweak in your BIOS to allow more than 4 GPUs to run simultaneously. We probably won't even hook a monitor up to the video cards at all after the initial install.
Also a little different is the process for installing an OS. You won't have a DVD Rom drive attached, so you can get a USB DVD Rom drive or plug a sata one in temporarily... or use a USB stick which is a snap with Linux but a pain for Windows 7. I run Windows 7, but Linux is probably best. Windows 10 I've heard is not the best for mining, so steer clear. You can plug a keyboard monitor and mouse into it but your best bet is to put it all behind a good firewall and set up remote access so you can log in to your mining computer without having to be physically next to it. Which isn't bad because the fan noise will be a little loud. It does make a great space-heater though. Seriously.
One last difference--we aren't putting it in a regular case. I mean you can pay for a specifically designed case, but... where's your DIY spirit?! If you are handy with tools and building stuff, that will help cut down costs (and increase fun-times value if you answered "yes" to the question in the first sentence) by building your own enclosure or frame. If you don't mind spending more and feel like being lazy you can buy pre-made frames and just secure the components, plug them in, and hit play. You won't use a normal computer case because this isn't a normal computer. The video cards will be spaced apart a little bit further than usual and you will want a good deal more airflow around them, since hopefully they will be working at as close to full capacity as possible, 24/7 until they die.
Okay so now you have a rig--that's right, you don't need me to tell you how to search the web for instructional videos or how to search electronics retailers for computer parts--so you turn it on, read some help files, install some software, get a few crypto wallet addresses, write a batch file or three and start mining. Building a crypto mining rig is not quite "plug and play", but nothing really easy ever returns as much value as your effort spent.
^^^ When you're done it might look something like this (This one's not mine, I found this picture on the interwebs. Mine is way uglier).
