This is a slight variation of a common trick you’ve seen if you have an adblocker.
You go to a site that makes its revenue from ads, and the site asks you to disable your ad blocker so they can continue to bring you great content. This is commonly done on newspaper websites. You get to see the content for free because they make a few cents on ad revenue from your visit.
If you take this idea and twist it a bit, here’s what happens:
Assuming you have ads of some sort on your site, offer to let your visitors have an ad free experience in exchange for joining your list. You can still offer a lead magnet, too, if you want. But the enticement of not being bothered by ads might just the ticket to get them on your list.
This will depend on numerous factors, so be sure to test. Also take note if those who subscribe to not see ads turn into paying customers.