This post is dedicated to SMB and her craftastic endeavors!
She asked for free apron patterns and the first thing I thought of was Tie One On. Each month there is a different theme and participants email photos of their aprons to the web site, which posts them for everyone to enjoy! I loved this Guys and Dolls-inspired apron – so clever and cool! As for patterns, under categories a few are linked.
Dorothy’s Aprons has reproduced patterns from a 1940-booklet by White Sewing Machine Company. Users can print and transfer the patterns, instructions are at the bottom of the linked page.
If that does not work, I would suggest using an existing apron for measurements to create your own!
ETA: I am not sure why the photo credit appears at times and then does not, but if you hover over it, the credit is there and if you click the photo it will take you to the Flickr group.