Spoiler: It's a horrifying number. Here's why.Have you been thinking about Spirit Airlines (SAVE 0.93%) lately? You might be, as its stock has fallen, arguably making its stock price more attractive to investors. You might even dream of how much money you could make, and might wonder how much you'd have today if you'd invested $10,000 in it a decade ago. Let's tackle these questions. First, let's look at how the stock has been faring. In October, my colleague Neil Patel asked, "Down 97%, is it time to buy S ...