www.dcbservice.com
I moved from my LCS after 8 years and I'm saving around 40% a month. They will ship international as well, but the shipping costs go up some. I think it is reasonable though, from what I've heard. You can get weekly shipping, twice a month, or once a month.
The service is great and the books come quickly. I did the calculation and I'm going to save around $1,200 a year from my LCS.