With Plesk there is no agreement to sign and you can upgrade or downgrade between different editions at any time.
In case you want to go big with Plesk, you can also check out our options to become a hosting partner to resell and/or use Plesk for larger installations and platforms. If you are an agency, a cloud or hosting provider or even indepedent developer or designer – Plesk can help you growing your business faster. We offer strong discounts between 15 and 45% on our retail licenses. The minimum commitment starts at 250$/month and includes a premium support SLA, a dedicated account manager and access to many partner-only resources. Visit our Plesk Partner Program page for more details.