We used to have a recycling center here in town that a guy could go to and salvage at. It was awesome! Stunk terrible bad... but you could buy scraps from them for your projects and build stuff for next to nothing. I think the most expensive thing that I bought there was $100 it was a 42" X 32" X Y table with a huge heavy frame and premium linear bearing and ball screws. It was awesome, I made a big CNC router from it which I used for years.
Unfortunately, that scrap yard doesn't allow you to salvage there anymore. It's a liability concern... I used to go there every few days and see what they had for new stuff. They would get packaging machines in there that were out dated and a guy could buy five gallon pail of pillow blocks and bearings for five bucks. Now, if you need anything like that around here you have to go to the store.... even though they have a ton of them they are just going to run through there four thousand horsepower shredder. Which I must admit is pretty cool... but it has really cut into my ability to hoard and stockpile stuff that I may eventually use. It really cuts into a guys creativity. I remember having nothing much going on and so I built an air powered digger for the kids sand box... my wife made me take it apart later that same day as it was way too dangerous for a pair of little kids to operate.. and it really was. Air powered stuff is fast! But, just the fact that a guy with a little ingenuity and some spare time could create awesome things for fun with out breaking the bank was great. Sadly though, now a days the safety patrol has all but put an end to it for many of us.
Yeah, there is still ebay and that does help a guy procure some cool automation pieces and parts, it isn't the same as getting a big pile of other peoples junk and finding a new use for it.