You don't go to many estate sales, do you?
Never been to one
Well, just so you (and others who have never been to an estate sale) know how things go, when they have comics, the usually price them per piece. Usually, it's $1 or $2 or $5 or sometimes $10. They very, very rarely differentiate the costs based on type or even age of comics.
To a person running an estate sale, a Roy Rogers comic from 1954 is just as popular (if not more) than a Haunt of Fear published the same month. And they may both cost $20. We know different, but they don't. And that's because estate sale companies' job is to empty out houses by selling as much as possible for as much as they possibly can. They may know that old comics are worth something the same way they know that old pottery is worth something or old tools or cameras.
Most don't have the understanding of all of the nuances of comics, because it's just not worth it to know a lot because they have to know stuff about everything.
They may see a #1 and think it's valuable, so you'll see Image from the 90s priced at $10 and high numbered comics from the 60s priced at $2.
However, there are rarely amazing deals at estate sales. This was a once in every 5 or 10 years type of a sale, especially considering the comics lasted until the day of the sale. (A lot of times they're sold before the sale begins.)
I do searches for stuff all the time, but it's no way to make a living (at least with comics). Now furniture or clothing or jewelry is another story, because every estate sale has that stuff.