http://www.viva-decor.us/pearl-pen This is a link for the manufacturer of the pens I used.
I have never seen them in Hobby Lobby, Michael's or JoAnn's. The ones I have were picked up at CKC in Tulsa last month. Given a choice, I prefer the Liquid Pearls but I can't find them in any of the craft stores in Oklahoma unless I buy sets with colors in them that I don't use.
I believe the pens are $5 and they probably hold over twice the amount of product that's in Liquid Pearls. You may need to do an online search to find a supplier.