Cheap uv resistant tarp will work, some kayak companies sell their own covers. Austin Canoe and Kayak has a good selection of generic covers and Mariner sails sells some as well.
Bert"Ipsa scientia potestas est"
-Knowledge in itself is power - Sir Francis Bacon "Beware the lolipop of mediocrity, one lick and you could suck forever"
- unknown author