Several retailers have inquired about installing Plexiglass shields at the check-out lanes in their stores, like Dierberg's and Hy-Vee's (see pictures below).
Here's some DIY information from our friends at Nebraska Grocery Industry Association.
Angela Barry and her husband installed their own Plexiglass shields in A Street Market in Lincoln, NE. The Plexiglass they used is 1/4" thick and 4'x27" wide. They used heavy duty, double-sided Velcro capable of holding 15 lbs to hold it in place. The total cost was under $100. The final result is the last pictured below.
Dierberg's
Hy-Vee
A Street Market