The spikes I used to create this look are called Screw Back Spikes and come in various sizes, colors & shapes. There are many internet sources to purchase them and I have provided links in the first step. I definitely recommend shopping around for different price points. Ebay seems to have some of the cheapest screwbacks, but they typically ship from Hong Kong, which can take a couple weeks to arrive.
If you've never used a power drill before, it's really no big deal. I recommended using an old shoe for practice first, before you start drilling holes in the heels you will use for this project.
I was able to create these shoes for less than $40 total, including shipping costs. (I already had the shoes).