Billy Warner and Carmen took me to MacPherson's on Sunday too get some cheap fruit and veg, and Carmen found a giant bag of nopales for only 79¢! I got them plus a nice, verging-on-overripe pineapple so I could make my favorite juice for upcoming work lunches. It's really easy: run 2 nopales, 1/2 a pineapple (peeled) and a lime (peeled) through your juicer. You should end up with about a pint and a half of juice, enough for two people. The cactus slime makes it thick and kind of chewy.
A nurse watched me drink it and wondered why I would bring such a thing in my lunch. 'Because I like it' was an inadequate excuse--cactus must have some health benefit or nobody would eat it. I looked into it and found that it's supposed to lower your LDL cholesterol, and be good for diabetics, and good for dieters because it's very filling per calorie.