Some people use the plastic that is used to cover fridges in grocery stores, etc., commercially. I don't know where you get this product.
You can also use clear carpet runner that is sold by the foot on rolls at places like Lowe's or Ace hardware, etc. This works pretty well too. I used some on the inside and outside and this did not phase my torts.
Its called vinyl strip door. If you do a GOOGLE shopping search you can then pick the cheapest place for you to purchase the strips. Bear in mind they come in different thicknesses and stiffness. You want one that will be flexible.