Nice book. A friend of mine makes a decent living of garage and (mostly) estate sales and swears by them. I've bought quite a few good things over the years myself for prices so ridiculous it's made me feel almost guilty at times, and of course I wasn't armed with any of those tricks. I've never visited garage sales on Fridays, for example. Didn't even occur to me. And their packing advice is really something, too. So yes, you absolutely can find treasure at garage sales, although not everything is, and sometimes it's laughable how much some folks are asking for pure trash. Well we all live and learn, I guess.
Due to a bed bug problem in many big cities across the US, please heed the authors' advice and do not buy used mattresses. Just say no, no matter how attractive the price is! Another piece of advice (from a New Yorker, so take it for what it's worth), be very careful with wooden frames and old paintings--they just love hiding there. Heard that from another guy who makes a living by killing those devilish creatures.
The authors are also dead on about estate sales. I've been to a couple, and felt a bit uneasy, because it seemed that pretty much everyone else was a professional. I know it wasn't the case, but people did come prepared. We ended up not buying much including the things we wanted because we couldn't gauge whether it was worth the asking price or not. Estate sales are more complicated, and are frequented by resellers and dealers, like my friend. It is hard to compete with those guys, so learn a thing or two before buying.
I gave this book 4 stars for one reason only: The TOC should be clickable. It's really easy to learn and it's a little frustrating when a reader has to go through all the pages in order to find the chapter they want to re-read. It's not a deal-breaker, however, because the book is not too long to begin with. If you're interested in garage sales at all, grab it. I don't see how you could be disappointed.