In-store opticians were once a great place to get specs directs, but with more fashion-forward brands launching online and even venerable brick-and-mortar shops offering web shopping, buying a pair of glasses has never been easier. And with a few exceptions, prices are comparable to online retailers.

The best online eyeglasses sites make it easy to provide a prescription, usually by letting you either upload a photo of your current frames or input the prescription numbers directly (like you would do at a doctor’s office). You’ll also need to know your pupillary distance (PD), which most sites ask for by placing crosshairs on a picture of your face and asking you to enter the number (it’s also sometimes possible to measure yourself with a ruler or to mark the inside of one of your existing pairs of glasses; see our guide for details).

Some online retailers are a little pushy about getting your business — for example, GlassesUSA requires you to be logged in to shop, and if you’re not, it will send you a persistent email inviting you back. Other online retailers, like Coastal and Eyebuydirect, are more careful about requesting your business, but still keep their prices low.

A few online retailers go a step further and let you use your insurance coverage to pay for part of the cost, but most of the lower-cost options, including Zenni, don’t accept insurance. Some of the higher-end sites, however, do (see our list of Best Glasses Sites for a full rundown). Eyebuydirect has an interesting philanthropic partnership with the Essilor Vision Foundation to help people who can’t afford glasses. And it’s among the few to offer a case with your glasses (unlike most other online sites that only include a box).