There are quite a few shops to be found in Orange County as well as the Greater Orange County Record Show held once a month. Also see my 2011 OC post here:
Port of Sound Record Shoppe - A real nice shop. Good selection in all genres. Lots of high end collectibles but also plenty of LP's for $6.99 Don't forget to look under the main LP bins as there is more stock down below in roll out drawers. Friendly owner and staff. I will be back. Highly Recommend. 1500 Adams St #102 Costa Mesa.
Factory Records - And the tiniest record shop in America award goes to.....Factory Records. Located in the high rent district in Costa Mesa. This shop is a bit hard to find, it's behind a barber shop on 17th. Plenty of free parking. If there are more than 3 people in here it's a pretty tight squeeze. I kept stepping on his inventory since its all over the floor and everywhere else. Some organization might help, but it's clear they are out of what little space they have. Decent stock. The bins are packed way too tight with LP's which makes it difficult to flip. My brother found some U2 12 inch imports, I found a Stones boot. Prices are a bit on the high end. Friendly clerk or maybe the owner? Recommended. 440 E. 17th St Costa Mesa
Left Of The Dial Records - This shop is small but nice. Lots of LP's in all genres. Decent prices. Friendly owner. I will be back. Located in the now trendy district of Santa Ana. I found a Frank Zappa promo and some jazz records. Recommended. 320 French St. Santa Ana.
Bionic Records - This place hasn't changed much in 30 years, which is about how long it's been since I've been in here. Lots of punk rock supplies like T-Shirts and stickers. The used vinyl selection was not impressive with most LP's starting at $12.99 in VG condition. They do have new vinyl if you are into that. I looked around for a bit and bailed. Not Recommended. 6012 Ball Rd. Buena Park.
There are several more record shops in the OC area, I will make this post now and add to it when I visit the other OC shops.