you know that saying ‘it’d cost an arm and a leg’

what do an arm and a leg actually cost and how on earth would you go about selling them to someone 

i sat there thinking long and hard about it and i had the mental image of going onto craigslist and seeing an arm for sale and you click the image and it’s just an arm.

an arm for sale 

and then it doesn’t sell so then the person tries to sell it in a lot 

with a leg

sitting there on some crappy white background with a nice shoe on to make it look presentable