To add 'example text' to a user sandbox page, two suggestions;

1. You can put {{subst:lorem}} to quickly generate random text - if I put that below, it makes...

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

...it is quite random; see Lorem ipsum. You can also put a number up to 4, to get several paragraphs, e.g. {{subst:lorem|4}}.

2. You can copy the entire text of any Wikipedia article, with a few caveats;

• Say where it comes from, in the edit summary - use a link to the specific dated revision from the page, for example;

This text copied from http://en.wikipedia.org/w/index.php?title=Sausage&oldid=386277439

You can get such a link by clicking on the History tab at the top of the article, ie in this case I went here.

• Remove any non-free images (logos, record-covers, etc) if any — they are not permitted in user space

• Add a colon-character : at the front of any categories, which should be at the end of the article. For example, changing [[Category:Breakfast foods]] to [[:Category:Breakfast foods]]. This stops the userspace page from appearing in those Wikipedia categories.

HTH, Cheers,