If you just need a single website, go with the free account with CMS hosting for one site.
To export, you will need a Lite Designer plan, and then you will need to find hosting elsewhere.
If you export, I assume you will have no hosting on the project. Forms will be continue to be sent to the project unless it has been deleted. Form submissions will also incur charges if it exceeds the amount allocated to your project’s hosting level.
Since you are new, I would also recommend looking at this ► [LIST] Feature Availability & Limits