If your objective is a circle template, you can just buy a pre-made circle template like this (just a random example for illustration):
Image courtesy Amazon
They're widely available at office supply or art supply stores, big retailers, online merchants like Amazon, etc.
If you want to make your own, the best tool depends on the type of plastic you're ...
You have an easy one, I think. The best tool for cutting the holes you describe, in template plastic is a hole punch, also known as a circle punch. A quick search shows that Amazon has all three sizes you describe.
3/4" - EK Tools circle cutter
1/4" - "Conventional" hole punch - 0.25"
1" - Cady crafts Punch
All of the above are ...