shooter69:eil.com have a huge catalog of vinyl.
Proceed with caution. For standard releases Eil.com is really over-priced in my opinion, and more so for "limited" editions.
Online I prefer Amazon, eBay (various shops, some excellent), Diverse Vinyl and for exclusive, luxury editions, The Vinyl Factory.
In the real world, it's record fairs, charity shops, and the surviving pockets of vinyl vending in Leeds, namely, Jumbo and Crash.