I have been going to garage sales since I was a kid, so I will chime in...
1. My biggest annoyance is the "eBay garage sales", people will have a garage sale, and when you find something, they go "Well I looked it up on eBay and they sell for $100, so howmuchyougimmie?"
I leave usually. People like this don't even know eBay, they look at active listings, not what stuff has SOLD for.
I do eBay as well. But I find it a slap in the face that people think they can put something that sold for $100 in front of maybe 100 people and sell it, vs putting it on eBay with over 100 MILLION people, photographing it, boxing it up, etc.
It's like they want all the money without all the work.
To me...a yardsale is "I have crap and I want it gone", and should be priced accordingly.
I've had a few sales myself, stuff that didn't sell on eBay. I usually ask 1/2 or LESS than I was asking (always ask within past selling prices), and stuff still doesn't move.
The biggest fit I through, is when someone advertised a "family tag sale" "generations of antiques" "priced to move" in a town a good hour drive.
Hoping to find some deals, I drove an hour, only to find out it was a ESTATE LIQUIDATION COMPANY....not a family, and they had EVERY THING looked up on eBay, and they did not want to take a dime less.
Every coat, pair of shoes, etc was looked up on eBay. I've never saw anything like it. Needless to say I got irate and called them out on their phony advertising.
2. I buy gold and silver scrap.
If you find say a small basket with maybe 50 little baggies of rings, bracelets, etc, and find at least a couple solid gold items, instead of digging through the basket, ask what they would take for the whole basket.
If it's not much, sort it out on your own time. There is about 5 people in my area who buy scrap, so spending as little time as possible at a yard sale is key.
It also prevents other people from hovering over you and digging through the basket. I hate when people do that.
If they seem like nice, chatty people, I usually leave my business card and tell them to call me if they run across more stuff, I've had a few good leads like this.
At one sale, I bought about $200 in gold scrap for a few dollars, so when the lady called with more, I paid it a little more than I usually pay to make up for it.
I feel bad when that happens, but you can't really go "you had 50 cents on this, but it's actually worth $50, so here's a $50 bill"
3. Quality yard sales are starting to become a thing of the past. Almost everyone knows a brother, aunt, cousin etc that has the capability to look stuff up on eBay.
So your typical yard sale anymore seems like clothing, kitchen utensils, books, etc.
4. I've been to some really odd yard sales.
I went to one once, and the couple was moving into a retirement home, they were in such a hurry to move, they literally told people everything was free, take it.
Then you have some where the family has no idea what anything is worth, so they put "make an offer" on a large sign.
I hate this. I always feel like I am going to either insult them, or overpay.
Then I went to one once, about 5:30am, they opened at 6:30. A lot of people open before they post they are open, and the phrase "the early bird gets the worm" prevails.
There was a line of about 5 people, I was 6th in line, standing at the gate. They yelled at the couple in front of the line, and said they are "trespassing and need to leave or they would call the cops".
Needless to say, that was a crappy business tactic. I doubt anyone else showed up.
I love garage sales 1st, auctions 2nd. Buying $100 items for $1 is always fun. The best I ever did at an auction...I bought a camera lens for $17.50 and sold it on eBay for almost $3,000 dollars.
