I havent been so lucky.. but my wife has been a few times..
She started hitting the goodwill and other thrift stores about a year ago.. mostly just tooling around looking to see if there were actual deals available or not.. she plays on a clothing re-sell site called Poshmark occasionally and was wondering where all these women were coming up with slightly worn, super high end fashion pieces and were able to make a business out of reselling them..
In just 5 or 6 visits she managed to pick up a couple of sets of designer shoes (I couldnt tell you the name) for less than $10 each... that she ended up re-selling on Poshmark for upwards of $100 each.. (apparently new from the retailer these were $500-$1000 type shoes)..
She was just "playing" and not really trying to do anything with it.. so it stopped after maybe a little more than month of swinging in a local goodwill about once every 5 or 6 days..
but it certainly proved that there is occasional treasure among the trash if youre willing to go look for it..
Where I have gotten lucky several times lately has been with online estate sales and auctions... I picked up a 16" poulan chainsaw that was in very good condition for $15 a couple of months ago.. got a 12" craftsman bandsaw for $30 (about a $300 saw in good used condition most of the time)... and last night I picked up a barely used 350lb Monarch deer feeder complete with solar charging kit, etc.. for $70.. (retails new for $250).. I also managed to get an old Bear Kodiak recurve bow for a buddy of mine (its right handed.. Im a lefty) for $50 thats in new/unused condition...