I didn’t want to order a heat sink for the Raspberry Pi 3. I wasn’t quite sure it needed one. I figured out it helped a little when I placed a Dime or Penny on the CPU of the Pi3.
I solderer 3 Dimes together with a blow torch. Got out the Dremmel and fixed them up. I liked the look so much that I spent 5 minutes polishing the dimes.
It helps enough to keep the Pi from under clocking during normal use. This whole project took about 10 minutes in total, which to me beats purchasing a heat sink. Besides, it’s a lot cooler.