For the last Year or so, Funeral Shock/ Case of Emergency vocalist and Record collector extrodinaire, Negative tom and I have split a table at the KUSF Rock'n' Swap. It's billed as the largest record swap in Northern California, but more accurately described, it's solid medium sized, mostly - but not entirely-vinyl record show that's held pretty regularly. All the proceeds from the door and the table rental help with the operating budget of the radio station - SF's main community free form radio station, so it's a worth cause ( and for what it's worth, I really recommend Carolyn Keddy's from MRR's show on Tuesday from Noon to 3 for the best in Garage Punk- always writing down band names when I tune in..
Over the years I've found a good bit of cool records at the KUSF swap- F " you are an Ep" 12", Confederate LP, Gears Lp ($2!), Black FLag KLOS interview LP, The ebba Gron 12" catalog, Minor Threat " filler" 7", Plugz LP, Zerstorte Jugend 2nd 12", Tools 7", Plane Jane and the Jokes 12", Varaus 1-sided 12" and 7", Los VIoladores 2nd 12", Decry 7", "Half Skull" 7", Sealed "Cleanse the bacteria", Die Kreuzen "Cows and Beer" 7", Follow Fashion Monkeys Lp are a few of the ones that stick out in mind, but I've bought stacks and stacks of vinyl there over the years..
The sellers at it are largley music fans who scower Yard Sales, Estate sell offs, Buy collections and generally do so to fund their record buying habits and pick up a few bucks. People get turned off by the "Record collector Fair" tag, but Prices of everything are rarely outrageous, often much cheaper than stores or online for more common stuff, and it's mostly a lot of dealers buying stuff off each other to keep, flog off on their online store, upgrade, trade or whatever. So come out. I sell A lot of old records of all types at this thing, but also now will sell Prank Titles at near-wholesale to encourage people to come out.
If you're not in the bay area, here's a couple spots I check to find record shows around the country:
Record Shows Of America
Record Collectors Guild ( Search forums)
When I was collecting records in the 90's all the good ( I.E. finnish and Swedish Hardcore) records were in the $1 bin, so get out there and dig, it's up to you to find, preserve and maintain the history!