Where to get correct pricing?

As a general rule, links documentation and service landing pages provide the most up to date information on AWS services and pricing. The link you pointed to before (https://aws.amazon.com/ec2/instance-types/t2/) has the most accurate information on pricing/ for T2 instances. The blog post linked is from 2014, and we have since reduced our pricing and introduced the t2.nano instances and new T families (you may want to check out our T3 instances since they are slightly cheaper: https://aws.amazon.com/ec2/instance-types/t3/).

I also recommend trying out the AWS Pricing calculator (https://calculator.aws/#/), which should also provide you an estimate and most up to date information on our pricing.