Being a tape scavenger can sometimes take a stronger reserve than many other collecting-centric hobbies. You often find yourself playing a mock game of Twister over toys spread on blankets while struggling to peer into a shoebox filled with VHS at a soccer mom's yard sale. Or you're under a table sorting through tapes in poor lighting with only the musty tablecloth keeping you company. Or you sense confused eyes looking in your direction while you wrestle to hold and pay for a stack of tapes while everyone else is raiding cheap DVDs mere feet away.
The key is patience and even though this sounds like "no shit" advice--look at every tape you come across be it at yard sales, swap meets, or perhaps even in the trash. Okay, the last one might not be the best idea. I'm not going as far to say crack open every case, but making sure your eyes pass by every cover or spine is vital since it comes down to just one tape being a keeper with surprising frequency.
This is something that seems less likely with DVD for some unknown reason. You can tell almost immediately you wouldn't find a coveted, long out-of-print horror disc if say, the box has titles like Beaches, Mask (as in Cher), or Hollywood Homicide. In contrast, VHS makes peculiar bedfellows regardless the age or sex of the seller. Gory little chestnuts axe their way in with aerobics videos and homebrew recordings of Spaceballs. Franco Nero in magnetic tape form stares in contempt at the two cassettes of The Frugal Gourmet by his sides. A bootleg 1972 version of David Hess with Japanese subtitles ponders whether or not he could hook up with Sharon Stone in that tape of The Specialist stacked behind him.
Again, if you have to, get your hands dirty rifling through old media. Countless times have I encountered a sprawling sea of VHS only to find one title that made it more than worth the time to look. My copy of Thorn EMI's hard case of The Evil Dead and Media's Demented both came from a little boy selling toys for pennies. The Last Mercenary came from an elderly gentlemen in a box of nothing else but John Wayne westerns. Hack O' Lantern was under a table in a box featuring no other horror flicks. My mint clamshell of The Body Beneath was amongst Disney clamshells like The Lion King and The Jungle Book at an antique mall. I have many more examples, but I'd be bragging...if I'm not already. It definitely pays to have a look-see at every stack you happen upon.