My local Walmart has individual DropStop Car, SUV, and Truck Seat Gap Filler on Clearance for $7. normally $9.98 or $19.99 for a pair sold on Amazon.
http://www.walmart.com/ip/Drop-St…t/33668123
Brickseek link: http://brickseek.com/walmart-inve…u=336681
This was a product from Shark Tank. Works on Driver and Passenger side. One size fits most vehicles.