This site was built to compliment the existing NetSuite Professionals Slack Community by adding a means for members to easily find answers to common questions and to create a searchable database of those questions and answers.

NetSuite Professionals

Can i give free shipping to a specific customer category without promo codes?

Using the promotion engine would be the best way. If you don't want to give out a code then you can just limit the audience to the specific customer category and then enable auto-apply promotions.

Other than that you could probably do scriptable cart but I would really recommend against that.