A Reddit thread about flipping cheap secondhand stuff just blew up 
It started with a $25 solid wood dresser someone grabbed because the seller said it was “too heavy to move.”
I wiped it down, tightened a couple loose handles, took better photos in daylight, and listed it again mostly as an experiment. Someone bought it two days later for $140.
The comments are packed with similar wins 
One person bought 26 original artworks at an estate sale for $160. Flipped individual pieces for $30 to $75 each.
Someone found a $5 hand-loomed blanket at a thrift store. Sold it on eBay for $240 
Another commenter lives at an apartment complex and picks up stuff people leave by the trash…
I’ve sold golf clubs, weights, dog crates, etc by doing basically nothing aside from taking a few pics and posting. Easy money.
One Redditor says they pulled in just under $10K in a year from garage sales, estate sales, and Marketplace browsing in their free time 
As someone else puts it…
It changes the way you think about literally everything. You see value in most things and begin to realize how much great stuff that has value goes to the trash.
To take this to the next level, add AI to the mix: $145 in 1 Day Reselling Free Items On Facebook 