In case you're not aware of it, freecycling is a movement in many cities over the world, where people advertise their old stuff that they don't need any more, for anyone who's willing to go and take it off their hands. A lot of people are hesitant about throwing away workable but old or mildly damaged things, but also don't want the hassle of putting it on ebay or craigslist and responding to a thousand questions.
In recent years, a significant portion of the items listings I've seen are about old electronic stuff that people have moved on from and want to give away.
If you asked me 20 years ago, I'd have given you good answers. Then? it was mostly a matter of collecting things. tell everyone you know that this is your hobby, especially teachers and people who work around computer labs. Tell them to let you have the stuff they are tossing. A good friend of mine would regularly patrol the university dumpsters, and got some really good stuff, including an obsolete sun enterprise that he conned a local ISP into hosting for $50/month for years (that thing was a 10 cpu monster; it ate way more than $50/month in electricity)
As for now? well, let's put it this way; I've still got two and a half working iphone 5 units in my parts drawer. I mean, none of them work, but I've got the parts for two and a half of 'em. I spent some time on it and decided to go buy a new iphone 7 instead (I kinda wish I went for the SE; the form factor of the 5 was superior, I think.)
Hell, I'm typing this on a macbook; I used to buy stacks of old thinkpads and just replace parts as they broke, but the thinkpads with the good keyboards are too old (the new thinkpad with the classic keyboard is too expensive, at least for a thinkpad sans ecc, and I always liked the X not the T) but... I got tired of that, too.
On the other hand, the macbook is kind of terrible. The keyboard is tolerable (better than the chicklet lenovo keyboards, but still only tolerable) and the wifi cuts out as if I had damaged the antenna in a fall, something i could totally repair on an old thinkpad.
But my point is that at this point I make too much money and don't have enough time to really have a good computer repair hobby.
I used the ifixit guides for my iphone 5 adventures; I personally think their toolkits aren't great (last one I got, for replacement of an iphone screen felt like it came with phillips rather than JIS drivers, and I think the iphone screws are JIS) -- but their videos and instructions seemed pretty good. On the other hand, none of the iphones I performed surgery on are fully functional, so...
In general I've had good luck with just looking the thing I'm doing up on youtube.
A while back, a friend of mine (a ce/ee) had a bad keyboard on her viao. Not having experience with the parts of the computer industry that don't require college degrees, she took it apart, and when she couldn't get it back together, she brought it to a computer repair shop.
The shop, of course, thought that the computer never worked; they also couldn't get it back together. (the wisdom here is to do all or none of the repair. The shop probably could have replaced the keyboard if she brought a working viao in with a broken keyboard... but because it wasn't working when they got it, aside from not seeing how it was put together, they probably thought it was broken more deeply than just the keyboard.)
So, on my thinkpads, I would download the manual and puzzle about in the exploded parts diagrams until I saw what was what. Thinkpads were pretty simple, though, doing this with the viao was just a giant tangle of wires.
Anyhow, I looked it up on youtube, and there was someone who had a real clear video showing how to take apart and put together a viao. Following the video, I found that the connector with the power button was plugged into the wrong place, and the viao worked perfectly.
My only real piece of advice comes from my working with servers. Go buy a ESD wrist strap and workmat. Ignore it when your friends make fun of you. It makes a difference.
