Waxed paper is my favorite. I have a 'butcher's roll' 30" x 600 ft in my cellar. Unfortunately, when using a spray accelerator (like ammonia & water) the CA will occasionally react with the wax (I think it gets hot enough to bubble the wax). I have also used:

The backing of Monokote (ask other builders as this is your first kit - save it thereafter).

Plastic painter's drop cloth.

Plastic table protector (for covering the lace tablecloth on your dining room table - check a fabric store).

Ploy bags for colleting trash paper - We have a shredder at work that uses 3' x 6' transparent bags. Somehow a couple found their way into my car trunk.

Poke around - you'll find something. Test any clear, poly/plastic material by putting a drop of CA on it and then a piece of balsa over it. After 15 minutes pull it off. If it sticks/melts find something else. If it doesn't then you're in business.