I'll sell a pound for what I paid which is $6 a pound and $5 for a small flat rate box. I've got 2 pounds to sell and the shipping is the same for 2 pounds if it fits in the box.

I bought 5 pounds of commercial pectin on ebay and that is a very large amount as it takes only 3 tablespoons to make 6 pints of marmalade. 5# was $29 delivered vs $18 for 1.5 pounds. I didn't know how strong this particular pectin was so I went for the 5 pounds. This stuff is much more concentrated than the grocery store kind and is for full sugar. I was able to double the usual boxed pectin recipe which is not usually recommended.

Grocery store prices for pectin are about $2-3 a box that makes 3 pints.

My recipe for 6 pints:
6 cups prepared citrus peel
10 cups sugar
3 tablespoons pectin