I am still also struggling with gaining strong and specific knowledge about what size/type needle to use when - b...ut as to the best place to purchase......I buy pretty much only Schmetz needles for all of my sewing/quilting/embroidery and always buy them from either Hancocks or Joanne's when they have their 50 - 60% off notions sale, or when I have a 50% off coupon. I always have a very generous supply of them on hand that way. Good luck in you" quest for "needle knowledge".