I have used AC Lens (
http://www.aclens.com/) a couple of times, and their service and price was
amazing. I purchased Boston gas permeable lenses (the small, hard ones). They put a mark on the right one, to help tell right from left, even though I had asked for the lenses to be unmarked. When I emailed customer service, they sent me a new one no charge, no shipping, and said to keep the old one as a backup.
When I told a local optician about the price they were charging, he said to go ahead and use them, since the price was below what his wholesale price would be.