Joni Mitchell once sang: "You don't know what you've got 'til it's gone." Sure, she was probably talking about time, friendships, and love, but we like to think the lyric could apply to just about anything — including beauty products.

After all, there's something so alluring about a sold-out product. You may have overlooked that new crimson lipstick before, but once the stock is wiped clean, you lust for it in a totally different way. (Translation: "The rest of the world loves this product, so I need to have it.") Sort of like non-buyer's remorse, if you will.

So, we decided to round up some of our favorite sell-out products in one convenient place. Ahead, check out seven that are flying off retailers' shelves. Missed your chance to buy, or simply want to try something new? We've gathered alternatives to each crazy-popular item, too.