Buying them both is way too expensive for me a student.
Open Office is an industry standard alternative to MS products. You are missing market share if you do not support Open Office
This is my first time giving a feedback and I don't know why programmers assumed that everyone uses powerpoint.
OpenOffice a free solution comparable to Microsoft Office. Build a plugin (extension) for OpenOffice's Impress and include it with your program as well as submit it for inclusion (http://extensions.services.openoffice.org/en/resources/user/submission) on the Extensions repository.