I would create two tiers.

One that's free and one that is "pro" that has a monthly or annual fee for access.

Depending on what you are providing you could offer a "super pro" marketed to businesses which gives them enterprise access to the content/services and charges a premium monthly fee.

Let anyone get limited access with a free account then establish a campaign to upsell people to Pro.
You will need to gate the pro content with a membership permissions system.

We have designed a few systems like this so if you want to chat book a 30 minute session and I'd be happy to walk you though details on how to go about it. Or help you think through your strategy.