I mostly gave up years ago much like MrWunderful said, it's mostly a loss and just painful and wasteful to even bother making an every day effort. All that effort to get something 1-5 times out of a 100 tries is not a win, it's more lost in time, money, gas, car wear and tear, you name it.
You're better off being a keyboard warrior looking for idiotically posted ebay listings. You know, far to low BIN set. Listing it as random item, but then failing to mention it also comes with the original box or inserts also burying that in later images that don't show up in the master down listing of auctions. Stuff like that you're far more likely to do better on. Locally look for nothing and stop, or look for anything and everything interesting, and if games happen to pop up there too one in a hundred times, then great. That's my way about it and it sucks far less. I've come across great deals on vintage electronics, antiques, cheap CDs, old 70/80s toys, decent digital cameras, and other interesting stuff. Some is kept, some isn't which then pays for the atrocious pricing on old games now.
Being aggressive won't even do you much good in most cases because some places stuff just doesn't turn up, or it turns up in bad places. Locally you'll find not that much vintage on craigslist, not so much at half price books either, but instead of small local chain of a few stores. That chain use to be a great deal, but after half price broke their back wiping their inventory due to how they price they had to match and exceed them. Now they have this fantastic inventory of used to new stuff from the NES forward but the pricing exceeds ebay so it's a museum to greed and failure. Yet people still keep dumping stuff there, maybe so they can revisit it a year or two later in the case for the memories.
