Do you do any buying or selling via social media? I have been doing LOTS of it, mostly selling but some buying as well.
As I said last week, I see many people selling on Instagram. I haven't yet, but that is my next enterprise.
There are a couple of Facebook selling pages I'm involved with — one is the Flea Circus, a local group which has about 1000 members. This is a closed group; you have to ask to join, and then be approved. There are only a handful of approved sellers (I'm one), and most don't ship (I do). So if you can pick up your purchase from the South Jersey/Philadelphia area, feel free to join!
One of the sellers there is my friend Jill from Vintageologie. She has amazing stuff, lots of it, and is a spectacular photographer/stylist to boot. I bought all of these items from her one day last week.
A dozen lovely green glass lidded bottles. I don't know whether to use them in my kitchen for spices or save them to embellish for Christmas.

A bunch of old wooden hangers -- I may transform these into something shabby chic. Or not. I kind of like the patina the way it is.

A bunch of vintage wagon wheels. Mr. VJIMT wanted them. In fact, all I had to say was "Jill just listed wagon wheels, do you want them?" and he bought them, sight unseen.

And then there's this. A vintage hotel room key rack.

So many things to do with it, as my Facebook friends have told me -- earring storage, show display, paint tube supplies…

I also sell on Country Cottage Auctions. Another closed group, but this site has buyers and sellers all across the US and Canada. There are two auctions a week, and I usually participate as a seller. I very rarely buy, but couldn't resist these tiny type trays… plus, the seller was local and I could pick up.
There is also the closed group Not2ShabbyVintage, where Kelley sells the many treasures she finds. She also runs the Upcycled Furniture South Jersey group, which is "secret" -- if you click on the link it won't take you anywhere, but if you are local and would like to join, go to Not2Shabby first and once you're in there you can request Kelley to admit you to Upcycled.
The sites I've mentioned only allow vintage, handmade, or re-purposed items for sale. However, there are many other yard sale types of groups on Facebook where you can get fun stuff and good deals. Type in your "town name" and "yard sale" in the search bar and a bunch should pop up.
On one of the yard sale sites, I bought a lot of 30 of these mason jar votive holders to resell, and am just hoping those darn stickers come off easily!

Feel free to share some of YOUR favorite sites in the comments, or on my Facebook page.