All purpose built "mobile" 12 volt bluray players I have seen are pretty darn spendy, it would be a lot cheaper to buy a "home" 120 volt player and run it off a small inverter (most players should draw well under 100 watts, so it doesn't need to be a big inverter). You can get cheap home bluray players for well under $50 these days, unless you plan to full time and this is your only bluray player, you won't need a fancy expensive one, for occasional bluray playback the sub $50 ones will be plenty good.