The process is exactly the same as if you were purchasing an item: click on ‘continue to payment’ and follow the usual steps. Obviously you will not be asked to provide payment details in the end, and therefore you will not be charged for anything.
This is a very practical sack for all kinds of things, but I like to use mine for clothespins - a camping necessity! It is worked in one piece, with a round bottom, ribs around the body of the bag and a simple drawstring. Choose a durable fibre, like cotton or hemp.
Find more from this designer at: http://www.ravelry.com/people/bohoknits