student pay
If I set up a course account for free, can some students use it for free while other students pay for upgraded access?
YES. Just see the due date by which the students have to pay to be at the end of the course. Give them the opportunity to pay for an upgrade for the first few weeks (say), then just unclick the student pay checkbox, thus no longer requiring them to pay at all. In short, whether they have to pay or not is something you can change at any time, they have a grace period before being required to pay, and you can change any of these settings at any time.
You can pay a one-time fee of $14 (per course) to move your student project to a Member Hosting and enable Internet Access, as shown in the screenshots below.
To use the option for the one-time fee, you must open your student project for the course you are taking. Student projects are named with the student name followed by the course title, like this: Jane Doe - MATH 101. If you don't see your course project listed under Projects when you login to CoCalc, it's possible that the instructor created your project using a different login (i.e. different email or name) than you are using, or that a login has been misspelled, or that you have not been added to the student list yet.
The teacher sets a deadline for course payment by the student. The deadline visible below the top row when you open the project.
If the course already started and the deadline passed, you are required to pay before you can access files in the student project.
Note: if you already have a subscription to CoCalc and have available upgrades, it is not necessary to pay the $14 fee; you can simply apply Member Hosting and Internet Access upgrades to your student project for the course in question.