Me, not caring about the latest & greatest, I often carefully & selectively buy used gear. I bought an older Tascam FW-1082 for $150 & a Tascam FW-1884 for $100 (Firewire based interface/mixer/controllers). These things were well over $1000 when new. Not that I'm recommending these interfaces for anyone else, but just that I got great deals on them was my point and I am happy with using them. You may want to look at buying a used RME interface maybe, then you'll still be getting great quality & low latency drivers. Or buy one brand new and spend a lot more.
As for computers, I've always built my own PC's. But this last time I took a chance, and at a recommendation, I bought an off-lease 'Work Station' type PC. Just this past year I bought an older Lenovo ThinkStation D-20, which came with two 6-core Xeon CPU's @3.06 GHz, 48 GB ram, Win 7 64 bit installed (with reinstall disk), 1100 watt power supply, and two 1TB 7200 RPM HDD's. The Lenovo cost me about $600 w/shipping. I couldn't even THINK about building a powerful PC like this at that price, not even with all used parts! I bought an SSD and use it for my OS/Programs drive, and use the 2 HDD's it came with as my Audio & Samples HDD's respectively.
The PC's I was interested in, were all older, high end Work Station type PC's, which aren't the typical off-the-shelf stuff, and are made for more serious work. I was looking at Lenovo ThinkStation D-20, HP Z800, Dell Precision T5500. They mostly come with Xeon's @2 to 3.4 Ghz per core (either quad or 6-core, with either single or dual CPU's installed). 800 too 1100 watt power supply, 8 to 96 GB ram, Win 7 64 bit or Win 10 64 bit. and various configurations of HDD's and/or SSD. There are of course other models of the same brands above, and can range in price from around $200 to $1,700 or more generally. Even at the cheapest prices of $200-$300 for used/off-lease systems...for which you'd likely get just one CPU, 8 to 12 GB ram, Windows 7 64 bit, and one or 2 HDD's, you can't go wrong.
These type of 12 core Work Station PC's with absurd amounts of ram, originally sold for about $3K to $4K.
I also bought an unused/sealed previously purchased copy of Cubase 8 Pro for $300 for my 12 core PC (same price as Cubase Artist!). Everything I got was at among the best deals available, and previously purchased/used. Being I'm not a pro for hire, I don't have/need to buy brand-new with warranties etc. If I can build my own PC, I can fix what may go wrong at some point.
Anyway, just my 2 cents food for thought on the above.