Purchases from Goodwill stores are usually decent deals if you know what to look for.
Goodwill stores, the chain of secondhand stores that are the public-facing arm of the American nonprofit corporation, accept donations of most items and resell them either in-store or online.
Goodwill has a close eye on donations (most of the time)
Goodwill overall pays very close attention to the donations that come into their doors. The truly valuable items are sold online rather than in the stores. They rarely make it out of the back room. Housewares, games, well-loved clothes, inexpensive furniture, etc., get sold in the stores.
It can be hit or miss though. One time I bought a box of Ikea light bulbs there for $8, and ended up reselling them on eBay for close to $100. The next time we went to donate some things, the person accepting them told me, “Sorry, we don't accept light bulbs.” This was some years ago, and when I went there a couple of weeks ago, there were several kinds of light bulbs on the shelves for sale. So, all I can say is that they either accept light bulbs, or they don't, take your pick.
I've also stopped checking eBay for price on things and started to buy things on a gamble. Some time ago there was some music equipment (a guitar board or pedal I think) that was marked $0.99. I got greedy and went outside to check the price on eBay before I bought it. When I came back, it was gone. One of the employees had taken it off the floor because they had mispriced it. Now I just put stuff that might be a steal in my cart.
The big one that got away
The last time I went to Goodwill, some of the new-in-package items were priced at a small discount to retail. The kind of price that would be a deal to someone who actually was looking for the item to use it, but not so low a price that someone could easily resell it.
I guess they're not really a B2B organization in that way, haha!
Which is why seeing Goodwill make a very public mis-assignment of value brings a smile to my face in a Jim Carrey kind of way: “So you're saying there's a chance!”
In my home state, Jessica Vincent visited a Hanover County Goodwill store and bought a very beautiful iridized vase for $3.99. Upon going home she researched the piece which eventually led to the assessment that it was a Carlo Scarpa piece of Venini Murano art glass, in pristine condition.
It later sold at auction for a tidy $107,100 … nearly 27 thousand times what she paid for it.
This is probably a once-in-a-lifetime score for Ms. Vincent, and easily beats my dealing at a flea market for collections of Vera Bradley (though I'm still tickled with that one.)
It does make me wonder how much stuff I've looked at over the years and missed how badly the value was assessed. To be fair to Goodwill, this vase may have arrived without fanfare in a box with some plastic refill cups from Dickey's or something — meaning that the donor may have had no idea what it was, either. It's the reason that I check my bills now for cool serial numbers — I don't want to miss things that go right through my fingers.
Goodwill finds from my recent trip
Even though I didn't recognize any six-figure deals this time, I did get a few things that probably weren't bad deals:

Dinosaur coffee mug (Cost: $1)
One of my daughter's good friends is really into dinosaurs. Our Goodwill has a couple of displays with coffee mugs. A lot of them were company swag or something similar, but this one was cute. It shows a drawing of a T-Rex that's just eaten a triceratops and is snapping a picture to foodbook his meal.
I looked up the cost of this mug and found $14 plus shipping, so I got a good deal on this one.
Glazed banana leaf tray (Cost: $4)
One of my splurges for myself every once in a while is nice-looking ceramic or glass bowls to collect stuff. It doesn't solve my clutter problem but at least things look a bit nicer than just stuffing my junk in drawers.
I ran across this leaf-shaped tray that is sturdy enough to inflict blunt-force trauma on an intruder. And it's pretty.
I researched this tray and my best guess is that it's a banana leaf shape. There aren't any identifying markings on it that I can see. It appears to be glass that's been painted on the bottom (a few flecks of the paint have come off).
So it's hard to tell if this was mass-manufactured or hand-crafted. Either way, it was four bucks, and it's now living next to the chair in my bedroom.
Framed black-and-white photograph of stained glass (Cost: $2)
My taste in art is mostly abstract and I'm drawn toward “mathy” things with simple shapes, so that's why I was drawn to this unassuming framed black-and-white picture of what looks to be stained glass (or windows, hard to tell).
The sticker from Target was still on the back. It's dated 2018 so these are on clearance online now for $5 plus shipping. So $2 for something to add to the wall of my office is pretty good for the shape it's in.
Actually … the more I look a how things are advertised on Target's site, the more I wonder if this was being sold as art, or as the frame. It makes me wonder if I'm doing what Rodney Dangerfield's dad did who “… carries around the picture of the kid who came with his wallet.”
Oh well. Find added value wherever you can, I guess!
What do you look for at Goodwill?
Let me know in the comments!