Case : I will have around 25-30 users who will be logging in (external users) to the powerpage portal once a month.
I am not able to understand which license should I get. I also need recommendation for powerapps portal license.
I checked the pricing in microsoft website and it gives me these 3 options.

I also want to understand if this plan is for developers who will need to login to powerapps and edit the portal or is it for normal end-users. Is this license supposed to be assigned to the Users through Azure portal?
My plan is to get Pay as you go subscription for power pages since I will only let authenticated users to log in.
I believe the pay as you go $4 plan would be sufficient for my case.

My goal is to keep the costs minimum.
Any suggestions would be appreciated.