sewing needles (sharps OR heavy duty will work best)
white thread (I chose polyester for added strength)
a thimble (I really recommend coin thimbles)
plastic bags of all types - grocery bags are easiest, but you can mix and match.
The thicker, more opaque bags will produce a thicker braid, while thin, more transparent bags will produce thinner ones. Try to get as many colors as you can - my basket is made almost entirely of white bags with very small amounts of color, and I think it would look even nicer with some full color bags mixed in.
I did lose track of how many bags I used to create this basket, but I'm guessing it was no more than 30. :)
SUPER FANCY BAGS TO LENGTH UPDATE: It took me 51 plastic bags to get 60 feet.
Not too shabby. I completed my latest rope in less than 8 hours of work, too! The latest rope is picture 2.