It depends on the type of yarn I bought, I have one and also have some yarn in hanks which I will have to use my winder so I can knit with the yarn.
A lot of mine is already sold in such a way that I can knit from it as bought, just find the middle end and away you go.
The only thing I'm missing is the swift, I used to have one but got rid of it when I got rid of my knitting machine.