A topic that's dear to my heart! I've stopped going to thrift stores altogether, after finding so little for so long. Waste of time and gas. EBay prices for the good stuff that still occasionally turns up are in the stratosphere (and I can't bring myself to deal "behind the scenes"; has always seemed like cheating to me). Haven't found a "keeper" at a garage sale or radio collector show in years. Flea markets are marginal, although every now and then a surprise turns up. (Seems to depend on the area of the country where the flea market is held.) And I'm afraid of craigslist. Sometimes (but rarely), just being in the right place at the right time produces a serious find, but it's never been because I was first in line when a flea market or garage sale opened (after all, even when you're first, you can't be first at every table).
In other words, I have no strategy for finding boomboxes anymore that I can count on with any degree of certainty. If anyone has a plan that works in even a slightly reliable way, I'd sure like to hear about it (no need to spill secrets, tho).
Fortunately, like many of you, I stocked up during the good years (before '80's memorabilia became fashionable) and stubbornly hold on to what I've got. And I've got a lot. Of course, I don't have every boomer I'd like to own, and I'm missing some important grails that I've never been lucky enough to run across. (Sometimes I think that the only way I'm ever going to snag another grail is if it falls out of the sky and and lands in my lap... or on my head!) Still, whenever I start to despair over how badly my sources have dried up and how my collecting has slowed down to a trickle (or, more accurately, an occasional drip), I think about what I already have, and that puts my mind at ease. It really is true that "you can't always get what you want." Which means that, even if I never get another boombox, I'll probably be OK.