I buy from Amazon because I've got a Prime membership and a rewards card. Before I had a credit card, I'd buy my paracord (and knock offs) from local hardware stores and outdoors/sports stores.

Military surplus sites are always good in my experience!

Here are some of the places I've ordered from:

http://paracordgalaxy.com/index.php?main_page=index&cPath=158

http://www.theparacordstore.com/

http://www.paracord.net/

I haven't noticed a lot of difference in the quality from one supplier to the next; if it's not extra-inexpensive-imported cord, it's probably good stuff.

Some additional thoughts:

I prefer 550 paracord if I'm going to braid with the whole cord, but if I'm going to remove the core strands, than 650 or some other type works fine too, as long as the kernmantle is the normal size.

Although I don't usually feel the need to do it, some people recommend washing the paracord before making something with it because it can have issues with shrinkage. (This is only if you are leaving the core strands in)

I would not recommend mil-spec cord for braiding projects. The kernmantle tends to be less uniform looking and makes the project look less well made. Type III commercial is what I like to get.

-Timothy Potter

I make all of my own dog leashes.  Synthetic cord is the only way to go.  Natural fiber leashes last only four to six months if that.  Synthetic fiber leashes last at least three or four years.  Recently I've been getting my Polypropylene and Nylon from The Tractor Supply.  Our local store has a pretty good selection.  Their prices aren't too bad.

Prototype.
Thanks all:)
Please critique as well!

As long as that connection point on the handle is solid I'd say it's perfect.. Maybe you could wrap the handle in leather?

lol I couldn't tell and I doubt your dog cares much either