This is a free pattern so I don't think you have to worry about selling it.
A purchased pattern may give you the copyright parameters. If it doesn't you can check the vendor's website. Most of the parameters state you can make and sell the item but only in a limited amount. What they are more concerned with is that you do not sell their pattern, or give it away, or copy it. Others ask you to get their permission before selling the item (I've only had to do this once). I've only had one vendor who said absolutely no but I didn't want to sell the quilt, I wanted to donate it for a fundraiser and she said that was ok.
If you are going to sell it, and it is someone's pattern, than you should include their information on the item and give them credit for the design. I usually do so by attaching a removable tag with their information on it.