Cases are 0$. Already have some.
You can spend $800 on a computer case if you put your mind to it
Or about $35 shipped for one that is functional
For the office computer, get a CPU/mobo combo deal at Newegg, pretty cheap.
That usually works out. You can get a good CPU/mobo combo for $90-$120. You can get cheaper than that but is usually is VGA out on the motherboard. But my minimum requirements are DVI or HDMI out onboard video
The PSU prices are for the absolute worst garbage you can find on the market. It will have low efficiency, produce unreliable voltages and will be loud. Don’t think of spending less than $50 for a “good” office computer, and expect to spend over $100 for a good gamer PSU.
My personal experience with ~$25 ThermalTakes and CoolerMaster has been zero problems
Monitor, $150 is fine for office, but for gaming you want better. LED backlight and IPS with a fast response make a gaming monitor, start at over $200 at 23”.
What I see is an LCD sweet spot of ~$130-140 for 23".
Peeps have been gaming for years with 2-4ms response time LCDs
Keyboard/mouse? Cables? Hard drive?
Does Apple include those things? Not on a Mac-mini
Samsung 1TB eco-green is $45 at New Egg right now but I see deals all the time for 500GB-1TB in the $40-$60 range shipped to your door
Overall, I think we have differing definitions of “good.”
BTW, we’re comparing to an iMac here, so count Bluetooth keyboard and mouse.
Yes, you can build a computer for much less than an iMac, but you will get much less than an iMac.