[lcrim]

Found this dual site from a thread over on the Asylum.  http://www.truebluemusic.com/  also  http://www.mosaicrecords.com/

Same people but slightly different focus for each site.  I am finding that used vinyl is nice but LP's that are in pristene condition are even better. These guys have decent prices and service (just received my first shipment from them). They stock a very, very  nice catalogue of jazz titles.  I found some very nice titles for just over $10 an LP and some truly amazing box sets (more expensive.)  
If you're into jazz on vinyl this is a great resource.

edit: They also sell CD's

[mjosef]

Thanks for the truebluemusic link, they got a nice selection of jazz vinyl. Good price too.

[hifitommy]

jazz and otherwise-used:

http://www.recordsbymail.com

just peruse the sections you want, youre likely to find SOMETHING you want.  and he delivers EXACTLY what is stated.  i got a classic reissue of blues in orbit that was stated to be mint minus.  it was perfect, AND his packaging is top notch.