looking for date-based prorated discounts.

I sell monthly subscriptions that need to have a prorated discount applied. If a customer purchases a subscription on the first day of the month they would be charged $30, $20 on the 10th day, $1 on the 30th day, etc.

Does such an extension exist? If not, what existing extension would require the least amount of modification to incorporate this functionality?

I'm a bit shocked that google search is only returning one instance of the word "prorate" in all of opencart.com. Is desire for prorating ability really that uncommon?

If this option would be popular, it would exist. You are looking for a very specific thing. Most 'similar' Places work on time slot solutions, so, one gets, by Example, 30 Days for 30 Bucks, starting Now. You will not find what your'e looking for, here, exept you get it programmed by one of the Pro's around here , but it could cost you around ~ 200 bucks easy...

I just ask myself how you want to use Opencart to 'selectively' allow Customers to 'see' something or not. Exept if you plan to offer your Subscriptions as Downloads only. But this only as comment, I may be way of track...

By cleaning up 2 'major' Harddisks, left by my dying PC #1, just 2 days ago, I shortly checked some 'found' PHP ZIP today, it's the Source found by adultwatchscript com, and I guess that something like that could possibly suit your requirements much better, after taking a look on the demopages of the site. It has individual customer handling and payment options built-in, but I did not check on details. But you could possibly modify it to offer 'Content' instead of Movies, or so...

Ernie