Someone mentioned this software on a Listserv I am on (thanks Pauline!) and I thought it should be passed on.
If you can’t afford Adobe Acrobat, you can use PrimoPDF (a free download) to make PDF files.
Even better, if you need a student to send you files in a “standard format,” the student can use the PrimoOnline file converter to upload a single file and receive the converted PDF file as an attachment to an email. This means there is no software download required (you know how students are with installing software … ). Also, if you’re on a computer with no PDF capability, you could use PrimoOnline too. Personally, I’m bookmarking this one!