There are several different types of these needles. there's the one's with a "V" in the top, ones with a slit in the side and the ones that have a spiral. I have never been successful with the ones with the "V" cotton thread always seems to break. I got the ones from JoAnn's, with the slit in the side of the eye. I think they were $10 for 8 or 10 needles. They work OK, but do make a large hole which goes away if you rub it, or launder it. The spiral ones are supposed to be wonderful, but should be for the price:
http://www.spiraleyeneedles.com/Needles.html