I will admit I did buy the official Eleven socks from the Halloween store. They cost $7 (rip off I know, but I didn't think I could find anything similar at Target or Walmart)
I bought a medium which would normally fit fine but this one was skin tight and barely covers my butt. I'm 5'4" for reference. Make sure you buy a size way bigger than you need if you buy this one.
The coat came from the men's outerwear section at Value Village. There were about a million jackets similar to this one and it only cost $5. The shoes were also from Value Village and cost $6.
I bought the waffles from the supermarket and I plan to tape them to the jacket or sew them on somehow for Halloween night so I don't have to carry them around.