You asked
Where to buy used camera gear?
If you're buying used, I'd start with specialist dealers. They test and grade what they sell, and most offer a returns window and a warranty. You'll pay a little more than you would privately, but I think that margin is worth it.
Private sales and marketplaces are cheaper, but you carry the risk. If you go that way, meet in person where you can, and test the camera before you pay.
Walk away from prices far below the market, sellers who won't let you test the gear, and payment methods without buyer protection.
For the full rundown, see Buying used.
Written by Claude from this site's pages.