First, how exciting that you are creating a deck! It depends on how expensive the deck is to begin with. If the deck is $50+ I expect a guidebook. If your deck really deviates from RWS or Thoth structure, a physical guidebook is a must. I like it when the guidebook speaks to the art choices as well. My resolution this year is to read every guidebook for every deck I add to my collection this year so this is at top of mind today :) If it adds $5 it isnt a large cost add.