DISCLAIMER: My mother used to make the neatest, loveliest little hand-wound balls of yarn, so I'm aware that it can be done.
Alas that is not one of my many talents, so don't judge me.
I've seen a lot of blog posts and forum posts letting all the neophytes out in the Internets know that, if you can only afford a ball winder or a swift, get the swift. Well, I'm here to tell everyone that this is, in my humble experience, crap.
First of all, if you can only afford one of the two, the ball winder is the less inexpensive of the duo, which means that the "extra" money can be put towards more yarn with which to use your new toy. I bought mine from JoAnn.com with one of those 40% off coupons for not terribly much a while back (if there's not a coupon, wait. One will show up in no time). Of course, there are lots of different options and different price ranges on eBay, Etsy, and all over the web if you want to go less commercial or lower-tech. There are some gorgeous nostepinnes out there if that's what you're after.
Secondly, one can always wind hanks of yarn around chair backs, lamp shades, or the unsuspecting feet of sleeping loved ones. Not all of us have the fortitude to wind a usable ball of lace weight by hand.
Thirdly, the ball winder makes your yarn into cakes. Anyone reading this blog not like cake? I dinna think so.
Of course, if you can swing both the winder and the swift, I highly suggest it. Nothing in this world is more fun that watching the colors of the yarn flashing as your swift and ball winder whirr in sync. Too bad that's not how we make real cake.