When establishing a subscription-based service, you could start with a freemium model. This works by giving people a free trial, giving them access to limited services or providing them with a service that includes obtrusive advertisements. Spotify is an example of a company that uses this model.
For paid subscriptions, consider dividing payment plans by audience requirements. For example, having a small business plan and a larger corporate plan. Offer more flexibility and functionality with each level of service people pay for.
Another option is to allow subscribers to have a base rate and then to pay for what they use on a monthly basis.