12v TV or use my laptop?

Help. I am not at all technical so please use simple language.Only my 2nd time out in my caravan and I like to use CLs, often without hookups. I remember 40 yrs ago, when caravanning with parents, we'd take a 12" TV that was powered off a 12V battery. I've seen the latest ones advertised but they're quite expensive. Opinions seem to be divided as to whether I can't just buy a £100 one from Argos thats 12V compatable, but if \i do that I believe I have to strip the plug down!! Can't I just buy a cable that fits into back of TV and has a 12v pin thingy at the end.......? Then, some people say I can watch TV on my laptop, but don't I need a fab signal for that? I can't even listen to radio 4 on my I-phone unless I've got my arms wrapped round  broadband router.........