I learned from a cheap kit ($13 or so) I got on eBay -- I figure in the beginning it's not as important because you're parking and drafting anyway (you don't need to keep the spindle spinning -- you spin it and hold it between your legs, then you draft -- thin out the fiber -- and let the twist into the yarn).
My experience: I started with the wool that came with the kit. Parked and drafted. Made sucky, rope-like yarn. Then I tried spinning silk hankies....and omg, A-HA moment. The spindle spun by itself, it was effortless and fun, and I was hooked. I went back to the wool and realized that perhaps it was the spindle that was my problem (couldn't keep it spinning when I was working with wool). So I bought a $16 Schacht Hi-Lo spindle and it made aaaaaall the difference. I
So yeah, it's really cheap to get started....the danger lies in that eventually you'll find yourself drooling over spinning wheels.
But really, there are plenty of us who make good, useable yarn in decent quantities, using only a spindle. :D
And it IS just like knitting....you don't spin 'cause it's cheaper than buying yarn, any more than you knit socks 'cause it's cheaper. (unless you have sheep and do all the dirty work, I guess
) You do it 'cause you enjoy it. :D