Balancing free and charged shipping in a Print on Demand store?

Hi community!

quick question regarding shipping cost. If I use 2 POD suppliers to my store:

  1. Printify = shipping cost
  2. Subliminator = free shipping

Is it normal for a store to have products with free shipping and shipping fee? How do I make it more homogeneous?

Sorry Am really new to this… Shipping strategy is my puzzle right now.

Thanks!