In the beginning a small fee will be required per transaction and longer term the goal is to be feeless in a similar way to hive. Regardless, the overall system is designed to be highly scalable, so even if there is a huge amount of network usage, you won't see a massive explosion in transaction costs.

The structure works a bit like this:

• Base fee 0.01 HBD
• Adjustable fee depending on execution cost (0.00-0.02HBD)

I intend fees to never go above 0.03HBD for 99.9% of transactions

That being said this is subject to change and a lot of the fee structures are somewhat arbitrary. The important factor in this is the system is scalability. What that fee ends up being will result in a natural balance between user operations & infrastructure backing.