If you're selling books on amazon.com and eBay, keep your eye out for those AA and other books geared toward alcoholics and families of alcoholics.
I recently listed an Al-Anon book (for families of alcoholics) and it sold on amazon the next day:
Of course, the best known alcoholic-related book is the AA "big book," the AA Bible. A first edition recently sold on eBay for $255, but more recent editions sell for decent money too.
Here's a second edition that sold for $38.85.
You can find this book everywhere: thrift stores, yard sales, charity shops, estate sales.
It's little wonder these books sell so well when alcoholism touches so many of our lives. I would bet everyone in the US knows at least one person in their extended family who is an alcoholic.
So keep your eye out for these books wherever you go. They're usually an easy turnaround.
Interested in other books that sell for big bucks? Download my ebook, Over 500 Books that Sell for $50-$5000 on eBay: http://www.yardsalers.net/500Books.asp