It's funny how lens.com requires a scan of a valid prescription and will not fill it after it expires-- stating something about a law. They even send email recommending that you stock up before it does. So I bought 2+ years worth, got ~50% "back" as "rebates", and then emptied their spend-tracking "rebate card" into the phone bill for the number they already had.
This must be merely what "increased access to eye exams and eye doctors" means in the USA.
Zenni lets you punch in your own numbers and takes your money and gives you glasses. These are a bit strong (my eyes have to adjust) but they are satisfactory.