Must Have Cards Under $5

Hi all, I’m very new to the game so forgive me if I misuse terminology.

I’m thinking of making my first ever 100 card singleton deck for Commander, but I have no idea where to start.

I’m aware there are good artifacts, instants, and creatures to have in almost any deck, I’m just looking to compile a list of anything $5 or under that’s a must have.

From there I think I’ll be able to see what color and type of deck I’ll build.

I’m very open to seeing suggestions, I hope this was enough information!