Aws ec2 instance comes with base ebs volume of 8 GB. You can install
Mysql,nginx,php7 on it. You can set up everything in 30 GB ebs volume. All you need is to extend the base volume size to 30 GB. You can do that while launching ec2 instance. You would need to consider the aws ec2 instance type. Basically do not choose free tier instance since you're hosting multiple sites. I would suggest to go with atleast t2.medium type instance
Aws ec2 instance comes with base ebs volume of 8 GB. You can install Mysql,nginx,php7 on it. You can set up everything in 30 GB ebs volume. All you need is to extend the base volume size to 30 GB. You can do that while launching ec2 instance. You would need to consider the aws ec2 instance type. Basically do not choose free tier instance since you're hosting multiple sites. I would suggest to go with atleast t2.medium type instance