I first tried to find what I needed at our local Home Depot, but only found two of the sizes I needed (sz 7, and something else). I then went to a local hardware store and found several more. I have also found that at different times I've gone into Home Depot (I carry my knitting needle gauge in my purse with me ), I've found different sizes available than what I might have found on the previous trip there.
I also bought 4 orange sticks at Sally's Beauty Supply. I think they were a size 7 (I'd have to dig them out to see). I had to check several in the bin before I came up with 4 of the same size to make a set.