depends -- are you looking for a single or double (for the car headrests)? For the latter, Walmart so far at $149.99 on BF...(thanks GD guys!!! Va to Oh is a long ride with two small ones!)
As for single, what size are you looking for, as that will make a difference too anywhere from 6 -10" and as you know, size DOES matter....(gonna leave that one alone...