I usually go to a thrift store about once a week but I really should stay away for awhile because I have a pile of rehabs projects that I haven't gotten to yet!
I think that the reason Gracie was only $2 was because she was not recognized as a "near-vintage Coach bag in good condition." The Italian Madison bags have a very different appearance and texture from the glove-tanned bags of the same era, and she was just overlooked. You can see before and after pics of Gracie at the thread below:
http://forum.purseblog.com/coach/meet-little-gracie-from-italy-an-unusual-rehab-664111.html
I like the Savers Thrift store the best because they have loads of bags that are well-organized and usually listed at decent prices. So I have a good chance of finding a nice "project" bag. And I can exchange a bag within 7 days if desired. (The Salvation Army and Goodwill Stores won't do returns or exchanges.)
But I have gotten some nice bags and good deals at both the Salvation Army and the Goodwill, mostly on bags that were in really bad shape when I bought them.
Any "half-way decent designer bags" are usually overpriced and locked away a the SA and GW. (But I have gotten lucky! I found my $2 Gracie at the SA and scored a vintage Christian Dior clutch in near-mint condition for $3 at the GW!)
One thing that I really don't care for at the Salvation Army store is their practice of writing the price directly on bags with marker and attaching price tags directly to the bag with staples! I think they should charge an extra dime and use a real tag!
However, the SA and GW are true charity organizations while the Savers donates a "portion of profits" to charities. And many thrift or consignment stores have no connection at all to any charity.
It's no big deal, but I always feel a bit better about blowing money on a vintage bag that I really don't need when I know that the money is going to charity.
Caution! I have seen overpriced, beat up bags and outrageous fakes at all thrift stores. That's why I try to stay under $20 (under $10 is even better in case I accidently buy a fake, and I have!)
Examine the bags carefully and get them authenticated here on TPF; keep in mind that many thrift stores will not do returns or exchanges. Good luck!