Amazon.com : Clear Reusable Plastic Envelopes with Snap Closure, Plastic Document Holders, 13" x 9" XL Size for Letter Paper, 50 Pack, by Better Office Products, Poly File Envelopes, Clear, 50 Pack :
Clear Small Plastic Envelope with Velcro, 6 x 9 Envelope
Amazon.com : 10 Pack Plastic Envelope with Snap Closure/Poly Envelopes,TFDLCG zm Clear Document Folders,A4 Letter Size(13"×9.5")for School Home Work Office,Assorted Colors : Office Products
Staples Plastic Envelope With Snap Closure Letter Assorted 9.875"h X 10.75"w Tr51798/51798 : Target
JAM Paper Poly Envelope with Snap Closure, Letter Size, Clear, 12/Pack (218S0CLG) | Quill.com
Small Poly Envelopes with Snap Closure, Set of 3 - Walmart.com