Many students understandably do not want to pay for shared hosting to post web design assignments online, but posting assignments online is far preferable to trying to send zipped up sites back and forth as changes are made. If the site is online, the student can simply make their changes and then the instructor and class can just revisit the website.
Here are some free hosting options that I recommend with some notes about each:
https://netlify.com -- Allows folder drag and drop or Github integration, the best choice for nontechnical design students. If you do not know Git, use their drag and drop interface.
https://surge.sh -- requires use of the command line to post and update but is easy to learn.
https://pages.github.com/ -- Slightly harder use of the command line to post and update.
https://codepen.io/ -- Easy for students to update as they just paste in html, css, and js but the overall structure of the page is obscured.
https://glitch.com/ -- Somewhat less easy than CodePen and also, as in CodePen, the overall structure of the page is obscured.