I have a (female) friend who uses coconut oil. I only use it with toys, and some toys react badly with anything but water-based lubes. Since I don't use it very often, it's not worth spending a lot of money on, so I go with Equate Water-Based Lube from Walmart. It's got no sugar in it, so it won't lead to UTI's, and it's safe to lick up when I'm done (doesn't taste that bad, unless I'm having a weird day).
All that aside, the absolute easiest time I ever had getting a larger toy in was when I wasn't quite completely cleaned out from my partner previously. So when I say a guy's cum is the best lube I've ever used, I'm not even joking. x.x It also makes for some damn good lotion on my skin.