I am after a twin in car DVD player set that allows you to watch two DVD's?

i was wondering if anyone can recommend where i can get one from, all i can see if a twin set that only allows you to watch same dvd there are sets that let each screen have their own dvd but they are rare out there any suggestions thanks i know argos do one for �150 but they were cheaper than that few years ago why didnt i buy one at the time!