I find it's less the houses, and more delusional people.
We saw some hilariously overpriced things when we went to a big community garage sale. People wanting $15 for tube tvs that were fairly old, $5 for a pair of not-very-fashionable shoes and $60 for a lululemon sweater. I just walk away.
There's a thrift store in my city that used to be great but has now gone down the crapper. They used to be very reasonably priced, at $5 for a bag of clothes. Now they're marking everything as 'special' so it doesn't go in the bag sale, and charging $12 for a cracked old leather jacket and $80 for a stained grad dress that is honestly ugly in the first place, which was priced at $20 before the management change. And 'vintage' (aka mostly old and faded and UGLY) clothing is now starting to get marked 'special' for no reason. They're getting greedy.
It's annoying. In either case you're selling USED items. I don't care if it's for charity, these are USED, and should be sold as such.