Hi there,

I'm wondering if Direct Admin will eventually switch to charging per account instead of per server. Is there any assurance on the pricing structure?

Without delving into the policies, my experience with nearly all software (and web hosting as well) is that when the company or the software is sold, there is no longer any guarantee of intentions being upheld. In other words, you cannot trust the present to predict the future.

As many have suggested, there are multiple factors that could lead to a price increase for DirectAdmin, particularly if it was sold. Therefore, the best approach is to appreciate the current pricing structure while it lasts.
However, switching from cPanel/WHM to DirectAdmin may not be advisable, as it would involve transferring all existing data and such efforts could be in vain if DirectAdmin was sold. Instead, it may be wiser to establish a new service, promote it more effectively, and avoid migration altogether.

I have not personally experienced such a scenario, but many domain registrars offer this feature free of charge. While registrars could technically charge a fee for any service, most will waive it to retain their clients.
But, if they do happen to impose a fee that applies only to you, it may be worth considering transferring your domain to another registrar.