Easiest way to lighten skin ?

I have my promotion on Friday and I have a horrible foot tan. I`m already using a sunless tanner on my feet, but my legs are still super dark! If you cover up the line, it looks like I`m two different people! I`m wearing flats with my dress and I`m really worried. I don`t have enough time or money to buy a spray-on tan for my feet, so I`m lightening my legs. I heard that lemon juice works wonders. Is that true? Any other home remedies? Thank you in advance! :D