Go to Amazon.com and into the search bar type
Free Christmas music
(You'll get a prompt saying "Free Christmas music MP3 downloads" and choose that.)
Across the top are two great albums, "Free Must-Have Christmas Masterpieces" and "Green Hill Christmas Music Sampler." The next two are one song each and the fifth one is Christmas at all (gotta love search engines).
Now, on the list below, click on "Sort by" and choose "Price low to high."
You'll get 17 free songs listed; five aren't Christmas music (see above).
Now you have 40 free songs -- that don't violate anybody's copyright -- from which to build your show.
HTH.
\dmc