Including shipping, and assuming you order enough stuff to qualify for Super Saver shipping, Amazon has the best deal on the 4-pack of Black & Decker 79-010-4 Workmate Swivel Grip Pegs at $8.36.
These are the standard dogs that B&D includes with the Workmate, precisely the items that are almost always missing when you buy a used one. I’ve used them to great advantage when holding items for planing and routing. And they’re made of plastic so you can accidentally cut into them without ruining your tool.
As stated above, there are a multitude of deals out there on the internet, but all exceed Amazon’s price when you include shipping. Second best is Ace Hardware on Amazon [What’s This?], $10.60 including shipping, if these are all you’re ordering,