Fun (for a certain definition of fun) and economical, but not what you want to do if you need to PC to work every day when you sit down at it.
PC power supplies, in general, are ticking time bombs the day you buy one. Buying a used one just ensures your PC fails even sooner.
Used third party ram makes me queasy too. It is a good price, but consider that at the RAM factory the lots go through statistical process control, lots rejected at that point still contain mostly passable chips which are probably sold at a lower price to the third party RAM suppliers. But there is something about the lot that isn't quite right.
There was a time around 2000 that whenever a Mac user called me with a flakey machine I used to say "Take out the extra third party ram you bought cheap two years ago when you bought the machine." A near 100% fix rate without having to ask any questions. It would work fine for months or years then start flaking out. I don't need that in any machine for which I'm responsible.
One of our departments is building its own machines from low priced components to save money. I think by any measure, the time it takes to find and remove the flakey ram modules and replace the disk drives that start having bad sectors 3 months into service has more than offset the cost savings.
I'm not sure I buy all of those arguments. Power supplies (cheap ones, anyway) are, indeed, of pretty mixed quality. But their failure rates show (in my experience, anyway) a distinct "bathtub curve", essentially failing within the first few months or not for several years. For a part like that, a used one can actually be more reliable than a new one, because you're essentially getting the "burn-in" for free.
And while, again, it's true that off-brand memory has higher error rates than premium stuff (which, generally, is coming out of the same fabs but testing at higher tolerances), the error rate is (1) still very low, I've only seen one bad DIMM over the last 10 years or so, and (2) trivially easy to test with memtest86. Got a bad stick? Yeah, it sucks, but you just replace it (for $20 or whatever) and move on. It's not a reason to triple your memory cost, IMHO.
And disk drives, in my experience, simply don't have a premium/bargain distinction in quality atall. Instead, these things fail in batches. Some 4500 RPM clearance models will churn for years, while some models of 15k RPM SAS monsters like give up the ghost within a few months. You can't win with drives.
You might be underestimating the amount of bad ram you have. I have often had RAM that would pass memtest but the system still became far more stable after changing the ram.
PC power supplies, in general, are ticking time bombs the day you buy one. Buying a used one just ensures your PC fails even sooner.
Used third party ram makes me queasy too. It is a good price, but consider that at the RAM factory the lots go through statistical process control, lots rejected at that point still contain mostly passable chips which are probably sold at a lower price to the third party RAM suppliers. But there is something about the lot that isn't quite right.
There was a time around 2000 that whenever a Mac user called me with a flakey machine I used to say "Take out the extra third party ram you bought cheap two years ago when you bought the machine." A near 100% fix rate without having to ask any questions. It would work fine for months or years then start flaking out. I don't need that in any machine for which I'm responsible.
One of our departments is building its own machines from low priced components to save money. I think by any measure, the time it takes to find and remove the flakey ram modules and replace the disk drives that start having bad sectors 3 months into service has more than offset the cost savings.