While not cheap, this portable DVD player is very reasonably priced. It has a nice tablet-like form factor that eliminates screen flipping, twisting or turning. It is very suitable for mounting on the back of a front seat for a cheap (not cheapo) in-car DVD system to keep kids entertained.
7" Portable DVD Walkman Player D-VE7000S - $119.95 shipped
7" Portable DVD Walkman Player D-VE7000S - $119.95 shipped