Where do you buy your contact lenses?

I’m looking for a cheap and reliable website to buy contact lenses at a discount.

I’ve Googled and found sites like CoastalContacts.com, JustLenses.com, etc. I was wondering if anyone has experience with these or similar sites and could recommend one.

I’d rather buy online for the sake of convenience, but if you know of a location in Durham, NC, that works too.

I don’t have a prescription here – I started wearing contacts before coming to America and I just need to buy new ones. I’ve heard Costco is good, but they require a prescription.