We found a few nice ones on Etsy but after a lot of browsing, we found a wonderful site that offered a free pdf. Included are labels for water bottles, food and a party sign. We found these at
Printabelle.com We entered the information using paint.net and printed them on glossy photo paper. White card stock would also work well for an invitation. If you are not familiar with a photo editing program, you can print and fill in the information after.