My market is private tennis clubs.
I am currently offering a free, no obligation 1 month trial with no long-term contract. Each customer has their own domain name and I customize each site to match their existing website's look and feel.
I show them testimonials from current customers, examples of how much time can be saved by moving from old systems (usually paper or an Excel spreadsheet) as well as dollar translations from time saved.
Once a customer signs up for the trial and begins using my system, they have already made the decision to keep it for years. The hardest part is having them make the jump, and the price keeps on showing up as the only obstacle. I've tried determining if it is a "fake no" and they have other reasons, but so far that honestly seems to be the only reason.
When you say way, way less, what would you expect for CPM? From reading around, a highly targeted audience (in my case, I know exactly what sort of income bracket, age, etc.) would have higher CPMs, up to $35. If I saw $5 CPMs I would be around $350, so I would need 3.5x the number of customers. I just don't know if $5 is even a number I would be close to reaching with my audience.
$50 a month should be a non-issue for my customers, even non-profit, member-owned ones.