You can't always get what you want....

...but if you try sometimes you can make what you need. Last fall I decided I desperately wanted a dark purple knit blazer. I searched in vain though. At the end of the season, I did find a knit blazer at Wal-mart that was on sale for under $10. It was bubble gum pink. I should have taken a before picture, I know, but I didn't so you will just have to use your imaginations.
Now, why on Earth would someone looking for a dark purple blazer buy a pink one? Simple: it was mostly cotton and there was dye to be had in the laundry detergents isle. Two boxes of purple and one box of denim blue later, I now have a blazer exactly the color I wanted.
My kitchen sink is no stranger to the dye packet. Last summer I bought a pair of chambray capri pants. I loved the cut and fabric. Try as I might, and in spite of the fact that chambray was insanely popular this summer, I just couldn't make them work in my wardrobe. I could have donated or consigned them, but when color turns out to be the only issue I have with an article of clothing, I don't consider that a reason to banish it from my closet unless it is a synthetic fabric that cannot be dyed. One pack of dark brown dye later, and I have a pair of capri pants that fit right in with the rest of my clothes and get worn often.
I will admit that dye doesn't always do exactly what you think it will, and if you are changing something that is already a color, that is when having a little knowledge of color theory comes in handy, but overall, I've had good luck changing things from colors that don't work in my closet to things that I love.