Allow using NAT & Service gateways instead of ephemeral public IPs in Always Free tier

Currently accounts in Always Free tier are not eligible for NAT and Service gateways.

This makes private subnets effectively unusable (as there is no way instances in private subnets can access the internet).

Besides, we have to assign public IPs to all compute instances we are eligible for (are not public IPs a finite resource?).

Could you please reconsider the limitation of zero NAT and Service gateways? This will allow us using private subnets, and we will not exhaust public IPs pool in cases, when we don't actually need them.