it all dependes on what your pattern calls for or how big you want your project to be
Any store should have knitting needles.
Knitting is accomplished usually with pairs of needles -- knitting needles, to be exact -- and some form of spun fiber spun into a long, long length -- usually several hundred metres long, and even longer.
knitting needles
20mm knitting needles are needles that are 20mm in diameter. They are also known as US size 35 needles.
Why?
A craft store, like Hobby Lobby or Joann's Fabrics has a variety of items for organizing knitting needles. Depending on the length of the various knitting needles, you might be able to gather them in a Pringles can if you don't want to purchase a roll-up organizer.
Knitting needles.
nooooooo!
no.
knitting needles
Yes, but you should probably be careful and take wooden ones.
Practically, a loom is used for weaving. Knitting is accomplished on a knitting machine or completed by hand using knitting needles.