Best place to buy used ds?

Most of your local record stores sell used CD's. Their prices will be a little higher than thrift stores but the CD's are categorized so you can browse more quickly and intentionally and will have been inspected for obvious defects and broken jewel cases. But the bargains are in the thrift stores if you have the time and patience. Good hunting!

Discogs.

Discogs, eBay and Mercari if I’m searching for a specific CD for my collection.  Beyond that church fairs and yard sales and estate sales.  

I go the garage sales. My last buy was 1100+ CD’s for $150.  I kept about 175, sold about 275 for about $150 and gave the rest to Saint Vincent’s. When all was said and done, I got 175 CD’s for free and I paid for my gas and I had a deduction for tax time. My wife stops into thrift shops and every now and then finds a SACD (for me) and a disk of something she likes.

Oh and if you have a used record store or Vintage Stock has 2 for one sales for every holiday.  They also have everything on their computer system so they can look for something specific for you.