Lens.com is based in the US with pricing in USD. They accept Mastercard, Visa, American Express, and Discover. They apparently accept money orders as well if you order by mail instead of online. They ship internationally to anywhere in the world. They have a direct and toll-free phone number, fax, email, and mailing address listed as contact info on their site. The BBB has them listed with an "A" rating, with a total of 139 complaints (137 resolved/closed, 2 unresolved).
Lens.com is probably one of the most popular contact lens companies out there. Their website is easy to navigate. You can select the lens you're looking for, sort by brand, or sort by type (daily's, monthly, colored, etc). and ordering is pretty quick. The selection is very high as well.
Pricing seems competative. Ordering multiple boxes usually results in a discount.
Lens.com claims that 90% of their orders are shipped the next day. For the remainder, it can take up to 5 days for them to receive stock. Orders placed on the weekend are processed the following business day.
When ordering, you have to create an account which involves entering your email address and creating a password. If you live in the US, there will also be a section during the order process that will ask for your optometrist's name (or store name), phone number, and patient name. According to the FAQ on the site, they will attempt to contact the optometrist to verify the information. If they don't hear back within 8 hours they'll assume the information is correct and proceed with your order. If you do not live in the US, it will not ask you for the optometrist info.
One thing I did not like was a hidden handling fee of 6.5% that's included in the subtotal. Setting up an order for a $35.95 box of lenses, the subtotal was between $38-39. While I'm not fond of handling fees to begin with (they should include it in the shipping or the base price), I'm especially not fond of magically adding it to the subtotal. It seems... well... sneaky. When comparing between online stores, make sure you compare the final totals.
To compare online stores, I use the pricing for a *single* box of daily, 1-2 week, and monthly lenses made by CIBA. If you get 2 boxes (1 for each eye, only necessary if your eyes have different prescriptions), you can double the expected supply listed below.
Granted, you may be looking for other lenses, but this should give a general idea of what to expect when comparing prices.
There are also faster shipping methods available via FedEx within the US at an additional cost.