For me, it has to be History without a doubt... Without travelling far and wide to pointlessly study it in university, all you'd really need to do is:
Write essays - I have a pen and paper, and a laptop to type documents
Read books - I'll get those from my local library which is a 5 minute bus journey. If I need extra books, I'll go on Ebay or Amazon
Field trips - Visit a few places related to whatever you're studying
These are all things you can do in your local town without spending a few grand on tuition fees. In an academic sense, why spend years in university accumulating vast amounts of student debt which you'll never pay back because there's no hope of getting a decent job with that degree?
I could get a Ph.D level of knowledge on the Crusades by sitting in my living room/study/bedroom and reading copious amounts of materials related to the topic over a few years.
History is a subject for the rich, pompous, middle-class scholars who didn't know what to do with their hefty parental allowances so they blew it all on pointless tuition fees for that pointless degree.
People studying History generally have nothing better to do than to loaf around sipping tea, nibbling crumpets and having senseless debates about the most pointless and outdated events which have long since been swept under the rug by anyone with an ounce of common sense.
Guy with common sense: Hi, what are you studying?
History student: History, you?
Guy with common sense: Psh... History? Well then, let's hope you're not living in a skip by the time you find out who killed the Princes in the Tower
Edit: (Negged by butt-hurt History students who can't face the truth)
Edit 2: (I've never applied for, nor have I been rejected for a History degree. I got 5 straight offers for Biochemistry which I am currently studying) BOOM.