As of 2015, the Purdue University online writing lab, the University of North Carolina libraries and the Regent University writing center all have MLA writing samples. In addition, AcademicTips.org and about.com have MLA sample papers.
Purdue University and Regent University have a sample paper downloadable as a PDF with annotations and explanation boxes. The University of North Carolina page has tabs with a sample works cited page, sample in-text citations, as well as rules on how to cite print and online sources. About.com uses six images of sample papers explaining how to format a title page, page with an image, works cited page, first page, an outline and an alternate first page. AcademicTips.org also has a full paper with explanatory annotations.