The pricing for Luminair subscriptions varies around the world, depending on region. Pricing is available under the "In-App Purchases" section of the App Store listing in your region.
In the United States, it's $9.99/monthly or $99.99/yearly for Luminair Standard (1-universe). It's $19.99/monthly or $199.99/yearly for Luminair Pro (4 Universes + some additional features like Scheduling and advanced triggers).
A feature comparison is available on the Luminair Pro page:
A single subscription give you access to all iPadOS, iOS and macOS versions.
The first 2-weeks are a free trial after signing up. You need to select and sign-up for a plan in order to utilize the free trial, but no payment is required at that time. You’ll only be charged if you decide to continue after the trial period ends.